Green’s Dictionary of Slang

(US) small, insignificant, physically slight.

1842		‘The Fishmonger!’ in Nobby Songster 37: It is shrimpy, skimpy, limpy, / When that it is in the pot, / But its rakey, flakey, shakey, / When in your hand you have it got.
1939		B. Appel Power-House 249: I’m through. Even shrimpy Bittsy’s better’n me.
1959		E. De Roo Young Wolves 75: Pa didn’t seem to be himself either. He seemed shrimpier than usual. Drawn into his shell.
1979		E. Torres After Hours 166: You take this shrimpie Filipino or Guamgay back in [...] Harlem.
1986		L. Heinemann Paco’s Story (1987) 182: He had a hold of her the way you’d grab some shrimpy litle fucker by the throat.
2003		T. Dorsey Stingray Shuffle 57: When a shrimpy guy is humble and quiet, well, that’s just pitiful.
2014		Ruderman & Laker Busted 63: I struggled to parrallel-park my shrimpy car.