Achish in Smiths Bible Dictionary

(angry), a Philistine king of Gath, who in the title of the 34th Psalm is called Abimelech. David twice found a refuge with him when he fled from Saul. (B.C. 1061.) On the first occasion he was alarmed for his safety, feigned madness, and was sent away.

Link: https://bible-history.com/smiths/A/Achish/