diff --git a/components/synedit/lazsyncocoaimm.pas b/components/synedit/lazsyncocoaimm.pas
index 915418eff3..caf38a0635 100644
--- a/components/synedit/lazsyncocoaimm.pas
+++ b/components/synedit/lazsyncocoaimm.pas
@@ -12,23 +12,31 @@
   3. mabye the support for MultiSelections in MultiCaretsPlugin is not perfect.
      for example, Shift+Arrow can only expand the Selection of the Main Caret,
      but not other Carets
+
+  macOS Lookup Word supported:
+  1. implement ICocoaLookupWord in LazSynImeCocoa
+  2. ICocoaLookupWord and ICocoaIMEControl can be implemented in different classes.
+     considering that LazSynImeCocoa is relatively simple, it is appropriate to
+     implement both interfaces in LazSynImeCocoa.
 }
 
 unit LazSynCocoaIMM;
 
 {$mode objfpc}{$H+}
+{$interfaces corba}
 
 interface
 
 uses
-  CocoaFullControlEdit,
   Classes, SysUtils,
+  Graphics,
+  CocoaFullControlEdit,
   SynEditMiscClasses, LazSynIMMBase, SynEditKeyCmds, SynEditTextBase;
 
 type
   { LazSynImeCocoa }
 
-  LazSynImeCocoa = class( LazSynIme, ICocoaIMEControl )
+  LazSynImeCocoa = class( LazSynIme, ICocoaIMEControl, ICocoaLookupWord )
   private
     _undoList: TSynEditUndoList;
     _IntermediateTextBeginPos: TPoint;
@@ -37,12 +45,18 @@ type
     procedure IMESessionEnd;
     procedure IMEUpdateIntermediateText( var params: TCocoaIMEParameters );
     procedure IMEInsertFinalText( var params: TCocoaIMEParameters );
-    function  IMEGetTextBound( var params: TCocoaIMEParameters ) : TRect;
+    function  IMEGetTextBound( var params: TCocoaIMEParameters ): TRect;
+  public
+    procedure LWRowColForScreenPoint( var params: TCocoaLWParameters;
+      const screenPoint: TPoint );
+    procedure LWLineForRow( var params: TCocoaLWParameters );
+    function  LWGetTextBound( var params: TCocoaLWParameters ): TRect;
+    function  LWGetFont( var params: TCocoaLWParameters ): TFont;
   private
-    procedure InsertTextAtCaret_CompatibleWithMultiCarets( var params: TCocoaIMEParameters ) ;
+    procedure InsertTextAtCaret_CompatibleWithMultiCarets( var params: TCocoaIMEParameters );
     procedure SelectText_CompatibleWithMultiCarets( var params: TCocoaIMEParameters );
-    function calcBound( var params: TCocoaIMEParameters ) : TRect;
-    function PosToPixels( const pos: TPoint ) : TPoint;
+    function calcBound( var params: TCocoaIMEParameters ): TRect;
+    function PosToPixels( const pos: TPoint ): TPoint;
   public
     constructor Create(AOwner: TSynEditBase);
     destructor Destroy; override;
@@ -159,6 +173,59 @@ begin
   Result:= FriendEdit.ClientToScreen( Result );
 end;
 
+procedure LazSynImeCocoa.LWRowColForScreenPoint(
+  var params: TCocoaLWParameters; const screenPoint: TPoint);
+var
+  localPoint: TPoint;
+  logicalPoint: TPoint;
+  pLine: pchar;
+begin
+  localPoint:= FriendEdit.ScreenToClient( screenPoint );
+  logicalPoint:= TSynEdit(FriendEdit).PixelsToLogicalPos( localPoint );
+  params.row:= logicalPoint.Y;
+  if params.row > 0 then
+    params.row:= params.row - 1;
+  pLine:= pchar( FriendEdit.Lines[params.row] );
+  params.col:= UTF8Length( pLine, logicalPoint.x ) - 1;
+end;
+
+procedure LazSynImeCocoa.LWLineForRow( var params: TCocoaLWParameters );
+begin
+  params.text:= FriendEdit.Lines[params.row];
+end;
+
+function LazSynImeCocoa.LWGetTextBound( var params: TCocoaLWParameters
+  ): TRect;
+var
+  p1: TPoint;
+  p2: TPoint;
+  lineText: String;
+  col1Bytes: PtrInt;
+  col2Bytes: PtrInt;
+begin
+  lineText:= FriendEdit.Lines[params.row];
+
+  col1Bytes:= UTF8CodepointToByteIndex( pchar(lineText), lineText.Length, params.col );
+  col2Bytes:= UTF8CodepointToByteIndex( pchar(lineText), lineText.Length, params.col + params.length );
+
+  // two vertexs in bytes
+  p1:= Point( col1Bytes + 1, params.row + 1 );
+  p2:= Point( col2Bytes + 1, params.row + 1 );
+
+  // two vertexs in pixels
+  p1:= PosToPixels( p1 );
+  p2:= PosToPixels( p2 );
+  p2.Y:= p2.Y + FriendEdit.LineHeight;
+
+  // client rect in pixels
+  Result:= TRect.Create( p1 , p2 );
+  Result:= FriendEdit.ClientToScreen( Result );
+end;
+
+function LazSynImeCocoa.LWGetFont( var params: TCocoaLWParameters ): TFont;
+begin
+  Result:= FriendEdit.Font;
+end;
 
 procedure LazSynImeCocoa.InsertTextAtCaret_CompatibleWithMultiCarets( var params: TCocoaIMEParameters );
 var