Where does “mongeress” come from?

mongeress (English) comes from English monger, from Middle English mongere, from Old English māngere, from Old English māngian — to trade, traffic, do as a monger.

Ancestry of “mongeress”, step by step

mongeress traces back through two separate lines of ancestry.

via English monger

Step	Language	Word	Meaning
1	English	monger	A dealer in a specific commodity; A person...
2	Middle English	mongere	A retailer; a merchant
3	Old English	māngere	trader, merchant, dealer, monger
4	Old English	māngian	to trade, traffic, do as a monger

via English ess

Step	Language	Word	Meaning
1	English	ess	The name of the Latin-script letter S; Something...
2	German	ess	first-person singular present of essen; singular...
3	Proto-Germanic	atiska-	grainfield
4	Proto-Indo-European	h₂edos-	sort of cereal, grain

Every word from Old English māngian →Every word from Old English māngere →Every word from Middle English mongere →