Green’s Dictionary of Slang

daffy n.2

also daffie
[abbr. dial. daffodil, a silly, showy woman]

(US) a promiscuous woman.

A.R. Macdonald Prison Secrets 65: ‘Who wusen’t ye on hand ter saa the daffie* the wardin lit in far the new confidence boarde?’ [...] *‘Daffie’ a cant word for a light woman.