IPA: //ʌnˈtaɪmli//
KK: /ʌnˈtaɪmli/
Happening at a bad or unsuitable time; too early or inappropriate.
His untimely arrival disrupted the meeting.
At a time that is not suitable or appropriate, often too early or unexpected.
His untimely arrival disrupted the meeting.
Untimely → It is formed from "un-" (meaning not) and "timely" (from Old English "timelic", meaning suitable or opportune). The word "untimely" means not suitable or occurring at an inappropriate time.
Think of 'not' ('un-') being added to 'suitable time' ('timely') — that's why untimely means something that happens at the wrong time.