Green’s Dictionary of Slang

poop n.3

[? abbr. nincompoop n.]

a fool.

[US]F. Remington letter 13 Nov. in Splete Sel. Letters (1988) 167: He’s good for soldiers but he would make life hell for poops & doods.
[UK]V. Woolf Voyage Out 51: They talk about art, and think us such poops for dressing in the evening [OED].
[UK]‘Sapper’ Final Count 839: They think I’m a positive poop — a congenital what-not.
[UK]Wodehouse Right Ho, Jeeves 129: We must always keep in mind the fact that we are dealing with a poop.
[US]P. Wylie Generation of Vipers 96: Poops and prickamice of every description have got themselves public offices, fortunes, and even what passes for literary reputations.
[US]K. Vonnegut ‘A Present for Big Saint Nick’ in Bagombo Snuff Box (1999) 168: They danced out of the house without their coats, saying things like, ‘Jingle bells, you old poop’.
[US]J.D. Macdonald Slam the Big Door (1961) 85: Those old poops that live there must’ve got a real earful that night.
[Aus]J. Dingwall Sun. Too Far Away 114: You stupid poop, how much did you lose?
[UK]Kirk & Madsen After The Ball 303: So one virtually must act out one’s most fleeting impulses in order to prove that one isn’t a hung-up old poop.