Unless
来自Big Physics
Safin（讨论 | 贡献）2022年4月26日 (二) 23:37的版本 （建立内容为“Category:etymology == google == [https://www.google.com.hk/search?q=unless+etymology&newwindow=1&hl=en ref] late Middle English: from on or in (assimilated t…”的新页面）
late Middle English: from on or in (assimilated through lack of stress to un-1) + less.
wiktionary
onlesse, from on lesse, from "on a less condition" ("on" became un-).
etymonline
unless (conj.)
mid-15c., earlier onlesse, from (not) on lesse (than) "(not) on a less compelling condition (than);" see less. The first syllable originally was on, but the quality of negation in the word and the lack of stress changed it to un-. "Except could once be used as a synonym for unless, but the words have now drawn entirely apart" [Century Dictionary].
