diff --git a/src/Compiler/Exception/CannotCompileMapperException.php b/src/Compiler/Exception/CannotCompileMapperException.php
index 36fad44..0192f93 100644
--- a/src/Compiler/Exception/CannotCompileMapperException.php
+++ b/src/Compiler/Exception/CannotCompileMapperException.php
@@ -39,7 +39,7 @@ public static function withIncompatibleSubtypeMapper(
         $subtypeMapperCompilerClass = $subtypeMapperCompiler::class;
         $subtypeMapperOutputType = $subtypeMapperCompiler->getOutputType();
 
-        $reason = "its output type '{$subtypeMapperOutputType}' is not super type of '{$mapperOutputType}'";
+        $reason = "its output type '{$subtypeMapperOutputType}' is not subtype of '{$mapperOutputType}'";
         return new self("Cannot compile mapper {$subtypeMapperCompilerClass} as subtype (#[Discriminator]) mapper, because {$reason}", 0, $previous);
     }