The Collaborative International Dictionary of English v.0.48:

Country cousin \Coun"try cousin\
   A relative from the country visiting the city and unfamiliar
   with city manners and sights.
   [Webster 1913 Suppl.]

Moby Thesaurus II by Grady Ward, 1.0:

43 Moby Thesaurus words for "country cousin":
   aunt, auntie, blood brother, brethren, brother, bub, bubba, bud,
   buddy, cousin, cousin once removed, cousin twice removed, daughter,
   father, first cousin, foster brother, frater, grandnephew,
   grandniece, granduncle, great-aunt, great-uncle, half brother,
   kid brother, mother, nephew, niece, nuncle, nunks, nunky,
   second cousin, sis, sissy, sister, sister-german, sistern, son,
   stepbrother, stepsister, unc, uncle, uncs, uterine brother