lateyoudaoicibaDictYouDict[late 词源字典]
late: [OE] English and Dutch (with laat) are the only modern European languages to use this word to express the idea of ‘behind time’. It comes from an Indo-European base *lad- ‘slow, weary’, which also produced Latin lassus ‘tired’ (source of English alas [13] and lassitude [16]). In prehistoric Germanic this gave *lataz ‘slow, sluggish’.

Its English descendant late originally meant ‘slow’ (and the related German lass still means ‘lazy’), but although this survived dialectally into the 19th century, in the mainstream language ‘delayed’ had virtually replaced it by the 15th century. From the same ultimate Indo-European source come English lease, let, and liege.
=> alas, lassitude, last, lease, let, liege[late etymology, late origin, 英语词源]
late (adj.)youdaoicibaDictYouDict
Old English læt "occurring after the customary or expected time," originally "slow, sluggish," from Proto-Germanic *lata- (cognates: Old Norse latr "sluggish, lazy," Middle Dutch, Old Saxon lat, German laß "idle, weary," Gothic lats "weary, sluggish, lazy," latjan "to hinder"), from PIE *led- "slow, weary" (cognates: Latin lassus "faint, weary, languid, exhausted," Greek ledein "to be weary"), from root *le- "to let go, slacken" (see let (v.)).

The sense of "deceased" (as in the late Mrs. Smith) is from late 15c., from an adverbial sense of "recently." Of women's menstrual periods, attested colloquially from 1962. Related: Lateness. As an adverb, from Old English late.