The Collaborative International Dictionary of English v.0.48:

Sharecropper \Share"crop`per\, n.
   A farmer who rents a parcel of land from its owner and pays a
   portion of the crop as the rent.
   [PJC]

WordNet (r) 3.0 (2006):

sharecropper
    n 1: small farmers and tenants [syn: sharecropper, cropper,
         sharecrop farmer]

Moby Thesaurus II by Grady Ward, 1.0:

44 Moby Thesaurus words for "sharecropper":
   Bauer, agriculturalist, agriculturist, agrologist, agronomist,
   coffee-planter, collective farm worker, crofter, cropper,
   cultivator, dirt farmer, dry farmer, farm laborer, farmer,
   farmhand, gentleman farmer, granger, grower, harvester, harvestman,
   haymaker, husbandman, kibbutznik, kolkhoznik, kulak, muzhik,
   peasant, peasant holder, picker, planter, plowboy, plowman, raiser,
   rancher, ranchman, reaper, rustic, sower, tea-planter,
   tenant farmer, tiller, tree farmer, truck farmer, yeoman