Green’s Dictionary of Slang

1. a cripple, often as a nickname, or term of contempt.

1895		N.Y. Times 22 Apr. 2/?: She was a frequenter of the east side saloons, and on Saturday night was in E. N. Garlands saloon [...] with Mickey Welsh, a song and dance man with whom she lived until recently; Teenie and Gimpy Amanda, two sisters, with whom she traveled, and a tall stout man.
1898		Hartlepool Mail 21 Apr. 3/5: Evans, commonly known as [...] ‘Gimpy Evans,’ for the reason [...] he is lame.
1904		J.A. Riis Children of the Tenements 24: Presently Gimpy, who limped, as his name indicated [etc.].
1925		G.H. Mullin Adventures of a Scholar Tramp 194: On the Road a lame man is a gimpy.
1931		W.N. Burns One-Way Ride 81: He was known to the patrons as Gimpy O’Bannion; he limped slightly.
1939		Exeter & Plymouth Gaz. 13 Oct. 11/4: Gimpy, a cripple, whom Jimmy [...] saves from going to a reform school.
1955		‘Hal Ellson’ Rock 2: I see how this Gimpy got his name. He’s a cripple.
1971		T. Thackrey Thief 163: I hadn’t forgot what old Gimpy had told me.
2002		R.C. Campbell Hall of Two Truths 33: That’s a good name for ’m [i.e. a dog]. Gimpy!
2013		T. Robinson Hard Bounce [ebook] ‘The fuck you want, Gimpy?’.

2. a police officer; thus a term of contempt.

1959

Murtagh & Harris Who Live In Shadow (1960) 55: Jimmy went down to the police and tried to get his card back [...] ‘Well,’ he tells, [...] ‘The gimpies told me no, I couldn’t have my license’. [Ibid.] 185: gimpies – The police; a mocking term for any people beneath one’s notice.

3. someone who is inadequate in some manner.

1968

G. Cuomo Among Thieves 289: And the screws themselves, they said, were either all gimpies or else a little stirbugs too, because who in their right mind would want to work in a place like that.