Green’s Dictionary of Slang

(orig. US) weak, effeminate.

1946		H.A. Smith Rhubarb 205: She began saying ‘eyether’ and ‘nyether’ and dropping her r’s like a pantywaist debutante.
1951		C. Willingham ‘Excitement in Ergo’ in Gates of Hell (1966) 176: Yaller, spec-wearing, burr-headed, panty-waisted niggers in bow ties and gray spats.
1962		(con. WWII) J.O. Killens And Then We Heard The Thunder (1964) 157: He’s got more get-up about him than all these trifling spoiled pantywaisted colored fraternity boys put together.
1971		A. Burgess MF n.p.: Some goddam British poet with one of those pantiwaist names, like Vere de Vere [R].
1991		B. Hamper Rivethead (1992) 151: We’re backin’ down like a bunch of panty-waist bank clerks.
2011		Independent 12 May 24/2: Mississippians do not share this panty-waist view.