A wheeler-dealer is a person who is always making deals — buying, selling, arranging, doing favours, putting people together and taking a cut. The word says three things at once: that there are a lot of deals, that the deals are complicated and hard to follow, and that the person is probably bending the rules somewhere. It is used most about business people, property agents, sports agents and politicians. The feeling is mostly negative, but not always strongly so — English speakers often say it with half a smile, the way you might describe a clever uncle who somehow always gets a good price. It is fairly informal, and a little old-fashioned; it belongs to newspapers and spoken English, not to formal writing. It is spelled with a hyphen, and the plural is wheeler-dealers. The activity is wheeler-dealing, and there is also a verb phrase "wheel and deal" — "He spent thirty years wheeling and dealing in Hong Kong." If you want to say someone makes many honest deals, don't use this word; say "a very good negotiator" or "a busy businessman" instead.