1Perfectly suitable or appropriate; very fitting. Also: perfectly suited; well-adapted. In later use chiefly predicative, especially with to, for.
2Of a garment, shoes, etc.: exactly adjusted or shaped to fit one's body; that is the right size or shape; close-fitting.
3Fully equipped or furnished.
Late 16th century; earliest use found in Richard Mulcaster (?1532–1611), schoolmaster and author. From well + fitted.