"a cowardly escape, an evasion," 1942; see cop out.
Entries linking to copout
cop out
by 1942, noun ("a cowardly escape, an evasion") and verb ("sneak off, escape, give up without trying"), American English slang, perhaps from cop a plea (c. 1925) "plead guilty to lesser charges," which is probably from northern British slang cop "to catch" (a scolding, etc.); as in cop a feel "grope someone" (1930s); see cop (v.). Sense of "evade an issue or problem" is from 1960s.