I. gaol ‧ bird /ˈdʒeɪlbɜːd $ -bɜːrd/ BrE AmE noun [countable]
a British spelling of ↑ jailbird
II. jail ‧ bird BrE AmE ( also gaolbird British English ) /ˈdʒeɪlbɜːd $ -bɜːrd/ noun [countable] old-fashioned informal
someone who has spent a lot of time in prison