From Wiktionary, the free dictionary
Tom o' Bedlam (plural Tom o' Bedlams or Toms o' Bedlam)
- (historical) A wandering mendicant discharged as incurable from Bethlehem Hospital, England.
- (archaic) Any wandering mendicant, either mad or pretending to be so.
- (archaic) A madman; a bedlamite.