1530s, "coming before the proper or usual time," from un- (1) "not" + timely (adj.). Similar formation in Middle Danish utimelig, of weather, etc. Old English had untidlic "unseasonable." Related: Untimeliness.
an untimely remark
alcohol brought him to an untimely end
unthrifty
untidy
untie
until
untilled
untimely
untitled
unto
untold
untouchable
untouched