fit and suit

These words do not mean exactly the same.

Fit refers to size and shape: if your clothes fit you, they are neither too big nor too small.

• These shoes don’t fit me – have you got a larger size?

Suit refers to style, colour, etc.

• Red and black are colours that suit me very well. (not … colours that fit me very well.)
• Do you think this style suits me?

Suit can also be used to say whether arrangements are convenient.

• Tuesday would suit me very well for a meeting.