Green’s Dictionary of Slang

self-satisfied, too smart for one’s own good.

1959		A. Sillitoe ‘Loneliness of the Long-Distance Runner’ in Loneliness of the Long-Distance Runner (1960) 23: ‘I came, I broke, I entered,’ like that clever-dick Borstal song.
2000		J.J. Connolly Layer Cake 112: He also unplugs the telephone cos they can be used to earwig conversations by clever-dick cozzers.