Or (feminine) mtsuwdah {mets-oo-daw'}; or mtsudah {mets-oo-daw'}; for matsowd; a net, or (abstractly) capture; also a fastness; --castle, defense, fort(-ress), (strong) hold, be hunted, net, snare, strong place.
KJV: And the prophet Gad said unto David, Abide not in the hold; depart, and get thee into the land of Judah. Then David departed, and came into the forest of Hareth.
NASB: The prophet Gad said to David, "Do not stay in the stronghold; depart, and go into the land of Judah." So David departed and went into the forest of Hereth.