1540s, "clean, free from dirt," from Anglo-French neit, Middle French net "clear, pure" (12c.), from Latin nitidus "well-favored, elegant, trim," literally "gleaming," from nitere "to shine," from PIE root *nei- "to shine" (cognates: Middle Irish niam "gleam, splendor," niamda "shining;" Old Irish noib "holy," niab "strength;" Welsh nwyfiant "gleam, splendor").Meaning "inclined to be tidy" is from 1570s. Of liquor, "straight," c.1800, from meaning "unadulterated" (of wine), which is first attested 1570s. Informal sense of "very good" first recorded 1934 in American English; variant neato is teenager slang, first recorded 1968. Related: Neatly; neatness.

"ox, bullock, cow," Old English neat "ox, beast, animal," from Proto-Germanic *nautam "thing of value, possession" (cognates: Old Frisian nat, Middle Dutch noot, Old High German noz, Old Norse naut), from PIE root *neud- "to make use of, enjoy."