The Collaborative International Dictionary of English v.0.48:

Peasant \Peas"ant\, n. [OF. pa["i]sant (the i being perh. due to
   confusion with the p. pr. of verbs), pa["i]san, F. paysan,
   fr. OF. & F. pays country, fr. L. pagus the country. See
   Pagan.]
   A countryman; a rustic; especially, one of the lowest class
   of tillers of the soil in European countries.
   [1913 Webster]

   Syn: Countryman; rustic; swain; hind.
        [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Peasant \Peas"ant\, a.
   Rustic, rural. --Spenser.
   [1913 Webster]

WordNet (r) 3.0 (2006):

peasant
    n 1: a country person [syn: peasant, provincial, bucolic]
    2: one of a (chiefly European) class of agricultural laborers
    3: a crude uncouth ill-bred person lacking culture or refinement
       [syn: peasant, barbarian, boor, churl, Goth,
       tyke, tike]

Moby Thesaurus II by Grady Ward, 1.0:

93 Moby Thesaurus words for "peasant":
   Babbitt, Bauer, Philistine, agriculturalist, agriculturist,
   agrologist, agronomist, arriviste, boor, bounder, bourgeois,
   bucolic, bumpkin, cad, churl, clod, clodhopper, clown,
   coffee-planter, collective farm worker, country, country bumpkin,
   countryman, countrywoman, crofter, cropper, cultivator,
   dirt farmer, dry farmer, epicier, farm laborer, farmer, farmhand,
   fellah, galoot, gentleman farmer, granger, groundling, grower,
   guttersnipe, harvester, harvestman, haymaker, hayseed, hick, hind,
   hooligan, husbandman, ill-bred fellow, kibbutznik, kolkhoznik,
   kulak, looby, lout, low fellow, lump, mucker, muzhik,
   nouveau riche, oaf, parvenu, peasant holder, peon, picker, planter,
   plowboy, plowman, provincial, raiser, rancher, ranchman, reaper,
   ribald, rough, roughneck, rowdy, rube, ruffian, rustic, serf,
   sharecropper, sower, swain, tea-planter, tenant farmer, tiller,
   tree farmer, truck farmer, upstart, vulgarian, vulgarist, yeoman,
   yokel