O.E. scrincan (class III strong verb; past tense scranc, pp. scruncen), from P.Gmc. *skrenkanan (cf. M.Du. schrinken), probably from PIE base *(s)ker- "to turn, bend." Originally with causal shrench (cf. drink/drench). The meaning "draw back, recoil" (c.1300) perhaps was suggested by the behavior of snails. The slang sense of "psychiatrist" is first recorded 1966, from head-shrinker (1950). Shrink-wrap is attested from 1961.