perlabori

Perlabori is a preposition welded onto a verb, and the preposition is doing the whole job. Per means by means of, so perlabori is to get something by working for it. The thing you get is the direct object, which trips people up at first: you do not perlabori at a job, you perlabori the money. Li perlaboras sian panon is he earns his bread.

The distinction from gajni is the reason the word exists. Gajni is to win or to gain, and it is deliberately silent about how: you gajni a prize, a match, a bet, an argument, and yes, a wage. Perlabori names the mechanism and insists on it. That makes it the word for a living honestly made, and it makes gajni the word you would use for the lottery. Esperanto does not usually bother with this kind of moral shading, so when it does, the shading is the point.

The pattern generalises, and it is worth noticing rather than stealing. Prefixing per- to a verb gives you a by-doing-this-I-got-that reading, and Esperanto will let you coin one on the spot, but almost none of them have stuck; perlabori is the one that earned its dictionary line. For the money itself you say salajro if someone pays it to you and mono if you are just counting it.