Among many other meanings, a suit is a jacket and pants that match — formalwear for men. Suits are well-suited (appropriate) for some jobs and formal events, like a funeral.
A suit is also short for a lawsuit — like when you file a suit against a doctor who removed the wrong kidney. A suit is also an appeal to someone who has something you want — like money or affection. In cards, the suits are hearts, diamonds, spades and clubs. If a hat looks good on you, it suits you. In fact, you can say of just about anything you like, "That suits me." Like a well-fitting suit, when something suits you, you enjoy it and feel comfortable with it.