inexpert, incompetent, humble, artless, unskillful, unprofessional, amateurish, semiskilled, crude, bad, more...

skilled, proficient, adept, experienced, competent

unskilled labor, unskilled worker, unskilled job, more...

lacking skill,   not proficient,   not at all skillful,   not skilled,   not adept,   without skill,   low skill,   not skilled at,   lacking the skill,   without any skill