"rope, chain, wire," mid-14c., "leader," from Old French guie "a guide," from guier (see guide, v.); or from a similar word in North Sea Germanic. The "rope" sense is nautical, first recorded 1620s.

"fellow," 1847, originally American English; earlier (1836) "grotesquely or poorly dressed person," originally (1806) "effigy of Guy Fawkes," leader of the Gunpowder Plot to blow up British king and Parliament (Nov. 5, 1605), paraded through the streets by children on the anniversary of the conspiracy. The male proper name is from French, related to Italian Guido.