diff --git a/src/main/java/net/minestom/server/command/builder/arguments/ArgumentDynamicStringArray.java b/src/main/java/net/minestom/server/command/builder/arguments/ArgumentDynamicStringArray.java
index e254e07f4..71689b35e 100644
--- a/src/main/java/net/minestom/server/command/builder/arguments/ArgumentDynamicStringArray.java
+++ b/src/main/java/net/minestom/server/command/builder/arguments/ArgumentDynamicStringArray.java
@@ -1,6 +1,8 @@
 package net.minestom.server.command.builder.arguments;
 
+import net.minestom.server.utils.callback.validator.StringArrayValidator;
 import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
 
 import java.util.regex.Pattern;
 
@@ -10,6 +12,10 @@ import java.util.regex.Pattern;
  */
 public class ArgumentDynamicStringArray extends Argument<String[]> {
 
+    public static final int RESTRICTION_ERROR = 1;
+
+    private StringArrayValidator dynamicRestriction;
+
     public ArgumentDynamicStringArray(String id) {
         super(id, true, true);
     }
@@ -27,6 +33,29 @@ public class ArgumentDynamicStringArray extends Argument<String[]> {
 
     @Override
     public int getConditionResult(@NotNull String[] value) {
+
+        // true if 'value' is valid based on the dynamic restriction
+        final boolean restrictionCheck = dynamicRestriction != null ?
+                dynamicRestriction.isValid(value) : true;
+
+        if (!restrictionCheck) {
+            return RESTRICTION_ERROR;
+        }
+
         return SUCCESS;
     }
+
+    /**
+     * Sets the dynamic restriction of this dynamic argument.
+     * <p>
+     * Will be called once the argument condition is checked.
+     *
+     * @param dynamicRestriction the dynamic restriction, can be null to disable
+     * @return 'this' for chaining
+     */
+    public ArgumentDynamicStringArray fromRestrictions(@Nullable StringArrayValidator dynamicRestriction) {
+        this.dynamicRestriction = dynamicRestriction;
+        return this;
+    }
+
 }
diff --git a/src/main/java/net/minestom/server/command/builder/arguments/ArgumentDynamicWord.java b/src/main/java/net/minestom/server/command/builder/arguments/ArgumentDynamicWord.java
index c4b88384e..df259bebe 100644
--- a/src/main/java/net/minestom/server/command/builder/arguments/ArgumentDynamicWord.java
+++ b/src/main/java/net/minestom/server/command/builder/arguments/ArgumentDynamicWord.java
@@ -1,6 +1,8 @@
 package net.minestom.server.command.builder.arguments;
 
+import net.minestom.server.utils.callback.validator.StringValidator;
 import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
 
 /**
  * Same as {@link ArgumentWord} with the exception
@@ -8,12 +10,20 @@ import org.jetbrains.annotations.NotNull;
  */
 public class ArgumentDynamicWord extends Argument<String> {
 
+    public static final int SPACE_ERROR = 1;
+    public static final int RESTRICTION_ERROR = 2;
+
+    private StringValidator dynamicRestriction;
+
     public ArgumentDynamicWord(String id) {
         super(id);
     }
 
     @Override
     public int getCorrectionResult(@NotNull String value) {
+        if (value.contains(" "))
+            return SPACE_ERROR;
+
         return SUCCESS;
     }
 
@@ -25,6 +35,28 @@ public class ArgumentDynamicWord extends Argument<String> {
 
     @Override
     public int getConditionResult(@NotNull String value) {
+
+        // true if 'value' is valid based on the dynamic restriction
+        final boolean restrictionCheck = dynamicRestriction != null ?
+                dynamicRestriction.isValid(value) : true;
+
+        if (!restrictionCheck) {
+            return RESTRICTION_ERROR;
+        }
+
         return SUCCESS;
     }
+
+    /**
+     * Sets the dynamic restriction of this dynamic argument.
+     * <p>
+     * Will be called once the argument condition is checked.
+     *
+     * @param dynamicRestriction the dynamic restriction, can be null to disable
+     * @return 'this' for chaining
+     */
+    public ArgumentDynamicWord fromRestrictions(@Nullable StringValidator dynamicRestriction) {
+        this.dynamicRestriction = dynamicRestriction;
+        return this;
+    }
 }
diff --git a/src/main/java/net/minestom/server/command/builder/arguments/ArgumentWord.java b/src/main/java/net/minestom/server/command/builder/arguments/ArgumentWord.java
index d596d3266..5a28ec3e2 100644
--- a/src/main/java/net/minestom/server/command/builder/arguments/ArgumentWord.java
+++ b/src/main/java/net/minestom/server/command/builder/arguments/ArgumentWord.java
@@ -20,7 +20,7 @@ public class ArgumentWord extends Argument<String> {
     protected String[] restrictions;
 
     public ArgumentWord(String id) {
-        super(id, false);
+        super(id);
     }
 
     /**
diff --git a/src/main/java/net/minestom/server/utils/callback/validator/StringArrayValidator.java b/src/main/java/net/minestom/server/utils/callback/validator/StringArrayValidator.java
new file mode 100644
index 000000000..a818399d8
--- /dev/null
+++ b/src/main/java/net/minestom/server/utils/callback/validator/StringArrayValidator.java
@@ -0,0 +1,8 @@
+package net.minestom.server.utils.callback.validator;
+
+/**
+ * Interface used when a string array needs to be validated dynamically.
+ */
+@FunctionalInterface
+public interface StringArrayValidator extends Validator<String[]> {
+}
diff --git a/src/main/java/net/minestom/server/utils/callback/validator/StringValidator.java b/src/main/java/net/minestom/server/utils/callback/validator/StringValidator.java
new file mode 100644
index 000000000..ca9e1a133
--- /dev/null
+++ b/src/main/java/net/minestom/server/utils/callback/validator/StringValidator.java
@@ -0,0 +1,8 @@
+package net.minestom.server.utils.callback.validator;
+
+/**
+ * Interface used when a string needs to be validated dynamically.
+ */
+@FunctionalInterface
+public interface StringValidator extends Validator<String> {
+}
diff --git a/src/main/java/net/minestom/server/utils/callback/validator/Validator.java b/src/main/java/net/minestom/server/utils/callback/validator/Validator.java
new file mode 100644
index 000000000..081f77971
--- /dev/null
+++ b/src/main/java/net/minestom/server/utils/callback/validator/Validator.java
@@ -0,0 +1,19 @@
+package net.minestom.server.utils.callback.validator;
+
+import org.jetbrains.annotations.NotNull;
+
+/**
+ * Interface used when a value needs to be validated dynamically.
+ */
+@FunctionalInterface
+public interface Validator<T> {
+
+    /**
+     * Gets if a value is valid based on a condition.
+     *
+     * @param value the value to check
+     * @return true if the value is valid, false otherwise
+     */
+    boolean isValid(@NotNull T value);
+
+}
diff --git a/src/test/java/demo/commands/TestCommand.java b/src/test/java/demo/commands/TestCommand.java
index e1396cbea..456458317 100644
--- a/src/test/java/demo/commands/TestCommand.java
+++ b/src/test/java/demo/commands/TestCommand.java
@@ -1,6 +1,5 @@
 package demo.commands;
 
-import net.minestom.server.MinecraftServer;
 import net.minestom.server.command.CommandSender;
 import net.minestom.server.command.builder.Arguments;
 import net.minestom.server.command.builder.Command;
@@ -18,7 +17,11 @@ public class TestCommand extends Command {
             //addSyntax(this::execute, dynamicWord);
         }
 
-        Argument test = ArgumentType.Integer("number");
+        Argument test = ArgumentType.DynamicWord("testArg").fromRestrictions(value -> value.contains("a"));
+
+        test.setCallback((source, value, error) -> {
+            System.out.println("ERROR " + error);
+        });
 
         setDefaultExecutor((source, args) -> {
             System.out.println("DEFAULT");
@@ -26,9 +29,7 @@ public class TestCommand extends Command {
         });
 
         addSyntax((source, args) -> {
-            int number = args.getInteger("number");
-            source.sendMessage("set view to " + number);
-            MinecraftServer.setEntityViewDistance(number);
+            System.out.println("HEY IT WORKS");
         }, test);
     }