WordNet (r) 3.0 (2006):

common man
    n 1: a person who holds no title [syn: commoner, common man,
         common person]

Moby Thesaurus II by Grady Ward, 1.0:

78 Moby Thesaurus words for "common man":
   Cockney, Everyman, John Doe, John Smith, Public, a nobody,
   a nothing, average, average man, body politic, bourgeois, cipher,
   citizenry, common run, commoner, commonwealth, community,
   community at large, dummy, estate, everybody, everyman, everyone,
   everywoman, figurehead, folk, folks, general public, generality,
   gentry, girl next door, homme moyen sensuel, insignificancy,
   jackstraw, lightweight, little fellow, little guy, little man,
   man of straw, mediocrity, men, nation, nationality, nebbish,
   nobody one knows, nonentity, obscurity, ordinary Joe, ordinary run,
   people, people in general, persons, pip-squeak, pleb, plebeian,
   polity, populace, population, proletarian, public, punk, roturier,
   ruck, run, runt, scrub, shrimp, small fry, small potato,
   small potatoes, society, squirt, squit, state, whiffet,
   whippersnapper, world, you and me