The Collaborative International Dictionary of English v.0.48:
jailbird \jail"bird`\, jail bird \jail" bird`\ A prisoner; one is in prison or who has been confined in prison. [Slang] [PJC]WordNet (r) 3.0 (2006):
jail bird n 1: a criminal who has been jailed repeatedly [syn: jail bird, jailbird, gaolbird]