Green’s Dictionary of Slang

turkey n.2

[turk n.1 (4)]

(US) an Irish immigrant; also as adj.

[Aus]Bulletin (Sydney) 12 Oct. 12/4: The Courtly Language of the Ring. / M’Murphy: ‘I gotcher beat, ‘Turkey’ – I gotcher beat!’ / Turkey: ‘Pooph! Oi’ll put me hook down yer t’roat and pull yez insoide out.’.
[US]T.A. Dorgan in Zwilling TAD Lex. (1993) 84: Just send him against some kaiser’s lad / Or maybe a wop or two / There won’t be much of that foreign bunch / When that turkey lad gets through.
[US]R. Lardner ‘Nora’ in Coll. Short Stories (1941) 378: I’ve got to have a spot for Joe Stein and he’d be a terrible flop as a Turkey.
[US](con. 1920s) J.T. Farrell Judgement Day in Studs Lonigan (1936) 821: They must be left-handed turkeys and Orangemen to be with this outfit.