butan, buton [OE]
but [MI]
https://www.etymonline.com/word/but#etymonline_v_18141
https://www.etymonline.com/word/by#etymonline_v_18164
https://www.etymonline.com/word/out#etymonline_v_9965
https://quod.lib.umich.edu/m/middle-english-dictionary/dictionary/MED6406
https://bosworthtoller.com/5503