Where does “-ing” come from?

-ing (Polish) comes from English -ing, from Middle English -ynge, from Old English -ung, from Proto-Germanic -ungō — -ing, -ion. "Forms gerund nouns from verbs.".

Ancestry of “-ing”, step by step

Step	Language	Word	Meaning
1	English	-ing	Used to form gerunds, a type of verbal nouns,...
2	Middle English	-ynge	Alternative form of -ing
3	Old English	-ung	forming nouns from verbs, denoting verbal action...
4	Proto-Germanic	-ungō	-ing, -ion. "Forms gerund nouns from verbs."

Words derived from “-ing”

grobbing
grobing
grzybing
hoteling

Every word from Proto-Germanic -ungō →Every word from English -ing →Every word from Old English -ung →