Old English cyssan "to kiss," from Proto-Germanic *kussijanan (cf. Old Saxon kussian, Old Norse kyssa, Old Frisian kessa, Middle Dutch cussen, Dutch, Old High German kussen, German küssen, Norwegian and Danish kysse, Swedish kyssa), from *kuss-, probably ultimately imitative of the sound. Related: Kissed; kissing. For vowel evolution, see bury. There appears to be no common Indo-European root word for "kiss," though suggestions of a common ku- sound may be found in the Germanic root and Greek kynein "to kiss," Hittite kuwash-anzi "they kiss," Sanskrit cumbati "he kisses."
Kissing, as an expression of affection or love, is unknown among many races, and in the history of mankind seems to be a late substitute for the more primitive rubbing of noses, sniffing, and licking. [Buck, p.1113]Some languages make a distinction between the kiss of affection and that of erotic love (cf. Latin saviari "erotic kiss," vs. osculum, literally "little mouth"). French embrasser "kiss," but literally "embrace," came about in 17c. when the older word baiser (from Latin basiare) acquired an obscene connotation. Insulting invitation kiss my ass is at least from 1705, but probably much older (cf. "The Miller's Tale").
Old English coss; see kiss (v.). It became Middle English cuss, but this yielded to kiss, from the verb. Kiss of death in figurative sense "thing that signifies impending failure" is from 1944 (Billboard, Oct. 21), ultimately in reference to Judas's kiss in Gethsemane (Matt. xxvi:48-50). The kiss of peace was, in Old English, sibbecoss (for first element, see sibling).
Keep it simple, stupid, or keep it simple and stupid (1980s+)
of affection (Gen. 27:26, 27; 29:13; Luke 7:38, 45); reconciliation (Gen. 33:4; 2 Sam. 14:33); leave-taking (Gen. 31:28,55; Ruth 1:14; 2 Sam. 19:39); homage (Ps. 2:12; 1 Sam. 10:1); spoken of as between parents and children (Gen. 27:26; 31:28, 55; 48:10; 50:1; Ex. 18:7; Ruth 1:9, 14); between male relatives (Gen. 29:13; 33:4; 45:15). It accompanied social worship as a symbol of brotherly love (Rom. 16:16; 1 Cor. 16:20; 2 Cor. 13:12; 1 Thess. 5:26; 1 Pet. 5:14). The worship of idols was by kissing the image or the hand toward the image (1 Kings 19:18; Hos. 13:2).