What does 1 Samuel 27:10 mean?

When Achish asked, 'Where did you raid today?' David would say, 'Against the southern part of Judah,' or 'Against the Jerahmeelites,' or 'Against the Kenites.' 1 Samuel 27:10 - Modern Text Bible

(David lies to Achish, pretending he’s attacking his own people or their allies, to keep Achish’s trust.)