c. 1400, "physical, human, mortal," from Old French carnal and directly from Latin carnalis "fleshly, of the flesh," from carnis "of the flesh," genitive of caro "flesh, meat," probably originally "a piece of flesh" (from PIE root *sker- (1) "to cut").
The meaning "sensual, pertaining to the passions and appetites of the flesh" is from early 15c.; that of "worldly, sinful, not spiritual" is from mid-15c. Carnal knowledge "sexual intercourse" is attested from early 15c. and was in legal use by 1680s. Medieval Latin carnalis meant "natural, of the same blood," a sense sometimes found in Middle English carnal.
also *ker-, Proto-Indo-European root meaning "to cut."
It forms all or part of: bias; carnage; carnal; carnation; carnival; carnivorous; carrion; cenacle; charcuterie; charnel; corium; cortex; crone; cuirass; currier; curt; decorticate; excoriate; incarnadine; incarnate; incarnation; kirtle; scabbard; scar (n.2) "bare and broken rocky face of a cliff or mountain;" scaramouche; scarf (n.2) "connecting joint;" scarp; score; scrabble; scrap (n.1) "small piece;" scrape; screen; screw; scrimmage; scrofula; scrub (n.1) "low, stunted tree;" scurf; shard; share (n.1) "portion;" share (n.2) "iron blade of a plow;" sharp; shear; shears; sheer (adj.) "absolute, utter;" shirt; shore (n.) "land bordering a large body of water;" short; shrub; skerry; skirmish; skirt.
It is the hypothetical source of/evidence for its existence is provided by: Sanskrit krnati "hurts, wounds, kills," krntati "cuts;" Hittite karsh- "to cut off;" Greek keirein "to cut, shear;" Latin curtus "short," caro (genitive carnis) "flesh" (originally "piece of flesh"); Lithuanian skiriu, skirti "to separate;" Old English sceran, scieran "to cleave, hew, cut with a sharp instrument;" Old Irish scaraim "I separate;" Welsh ysgar "to separate," ysgyr "fragment."
"carnal union of males with males," especially "sodomy of a man with a boy," c. 1600, from French pédérastie or directly from Modern Latin pæderastia, from Greek paiderastia "love of boys," from paiderastēs "pederast, lover of boys," from pais (genitive paidos) "child, boy" (see pedo-) + erastēs "lover," from erasthai "to love" (see Eros). Related: Pederastic.