Probably from karath in the sense of executioner; a Kerethite or life-guardsman (compare tabbach) (only collectively in the singular as plural) -- Cherethims, Cherethites.
KJV: We made an invasion upon the south of the Cherethites, and upon the coast which belongeth to Judah, and upon the south of Caleb; and we burned Ziklag with fire.
NASB: "We made a raid on the Negev of the Cherethites, and on that which belongs to Judah, and on the Negev of Caleb, and we burned Ziklag with fire."
KJV: And all his servants passed on beside him; and all the Cherethites, and all the Pelethites, and all the Gittites, six hundred men which came after him from Gath, passed on before the king.
NASB: Now all his servants passed on beside him, all the Cherethites, all the Pelethites and all the Gittites, six hundred men who had come with him from Gath, passed on before the king.
KJV: And there went out after him Joab's men, and the Cherethites, and the Pelethites, and all the mighty men: and they went out of Jerusalem, to pursue after Sheba the son of Bichri.
NASB: So Joab's men went out after him, along with the Cherethites and the Pelethites and all the mighty men; and they went out from Jerusalem to pursue Sheba the son of Bichri.