masc. proper name, name of the first of the Patriarchs in the Old Testament, from Hebrew Abraham "father of a multitude," from abh "father" + *raham (cognate with Arabic ruham "multitude"); the name he altered from Abram "high father," from second element ram "high, exalted." Related: Abrahamic; Abrahamite.
Abraham-man was an old term for mendicant lunatics, or, more commonly, frauds who wandered England shamming madness so as to collect alms (1560s). According to the old explanation of the name (from at least 1640s), they originally were from Bethlehem Hospital, where in early times there was an Abraham ward or room for such persons, but the ward might have been named for the beggars.