FLK noun a strange-looking child; a funny-looking kid US,1961 Recorded in an article about medical slang in British (3 London and 1 Cambridge) hospitals.
[O]nly have come up with the residents’ slang expression FLK for “funny-looking kid.” — ArchivesofNeurology, p. 32, 1969
— Maledicta, p. 117, 1984–1985: “Milwaukee medical maledicta”