XXku-shi: This name represents kushi, in the original Septuagint Chousei, Chousi), either with or without the article. With the article (so in 2 Sam 18:21-32 seven out of eight times, all readings supported by the Septuagint) it simply indicate that the person so designated was of the Cushite people, as in Jer 38:7 ff. Its use without the article has doubtless developed out of the foregoing according to a familiar process. For the Cush of Ps 7, title read "Cushi" with Septuagint.
(1) The messenger (the Revised Version (British and American) "the Cushite") sent by Joab to acquaint David with the victory over Absalom. That this man was in fact a foreigner is indicated by his ignorance of a shorter path which Ahimaaz took, by his being unrecognized by the watchman who recognizes Ahimaaz, and by his ignorance, as compared with Ahimaaz, of the sentiments of David, whom he knows only as a king and not as a man. 2 Sam 18:21 (twice, the second time without the article), 2 Sam 18:22,23,11 (twice), 2 Sam 18:32 (twice).
(2) The great-grandfather of Jehudi, a contemporary of Jeremiah (Jer 36:14). The name Jehudi itself ("a man of Judah") is sufficient refutation of the opinion that the use of Cushi as or in lieu of a proper name "seems to show that there were but few Cushites among the Israelites."
(3) The father of Zephaniah the prophet (Zeph 1:1).
J. Oscar Boyd