Judy

   a prostitute

   The derivation is either from the common girls' name which became a name for common girls or, more probably, from Judith, the beautiful Jewess who is said to have tricked Nebuchadnezzar's general Holofernes in order to save the town of Bethulia. The general lost his head to her and to the axe:

    When monks like Negga were shooting down their officers or bribing potential Judiths to seduce their Holofernes... (Mockler, 1984)

   Then a Judy became a mistress:

    He went tul his wife at Wortley, an his judy went to Rotherham. {Dewsbury Olm, 1866, quoted in EDD)

   And now, in Ireland at least, she is an attractive young woman:

    Some great lookin' judies. (R. Doyle, 1987 — the advantages of a public house were being discussed)