to work for free, to work without pay or other compensation / to work in vain, to work with no favorable end result

(archaic, grammar) any word that declines or conjugates / (archaic, grammar) more specifically, a verb

each person

one person

one person / singleness, singularity / one's own efforts or strengths / an unmarried person, single

shipbuilder, shipwright, a carpenter who builds boats

(of feudal Japan) Synonym of 宮内省 (Kunaishō, “Ministry of the Imperial Household”) (designation by the Chinese) / (of pre-modern Japan) Clipping of 工部省 (Kōbushō, “Ministry of Public Works”).

welder

plumber

(dated) plumber