unskilled person - a person who lacks technical training

abecedarian - a novice learning the rudiments of some subject

apprentice, prentice, learner - works for an expert to learn a trade

cub, greenhorn, rookie - an awkward and inexperienced youth

landlubber, landsman, lubber - an inexperienced sailor; a sailor on the first voyage

fledgeling, fledgling, newbie, newcomer, entrant, freshman, neophyte, starter - any new participant in some activity

tenderfoot - an inexperienced person (especially someone inexperienced in outdoor living)

trainee - someone who is being trained