Green’s Dictionary of Slang

1. a weakling; a ‘kill-joy’.

1923		G. Mcknight Eng. Words 61: Youthful impatience with anything or anybody that interferes with a good time is expressed by such names as kill-joy, frost, wet-blanket... To these may be added, from the language of girls, [...] cuckoo, old priss, old Jane. [Ibid.] 62: If she [i.e. a girl] is unpopular, she is [...] a priss, a tomato, a chunk of lead, a drag.
1953		W. Eyster Far from the Customary Skies 37: A few bold sailors directed hisses at the Executive Officer. ‘Priss, prig, prude,’ sounded a voice.
1981		O’Day & Eells High Times Hard Times 36: I was only fifteen and acted like Miss Priss.
2000		M. Collins Keepers of Truth 68: Fred, that blond jock, always gets that priss, Daphne, alone.
2012		C. Stella Rough Riders 229: She’s a priss [...] That woman’s never had a hard day in her life.

2. (US campus) an effeminate man.

1967–8

Baker et al. CUSS.