Where does “smoothe” come from?

smoothe (Middle English) comes from Old English smōþ, from Proto-Germanic smanþiz — flat, smooth, soft.

Ancestry of “smoothe”, step by step

Step	Language	Word	Meaning
1	Old English	smōþ	smooth, serene, calm, unruffled
2	Proto-Germanic	smanþiz	flat, smooth, soft

smoothe — Etymology, Origin & Word History | Etymology Explorer