Noun formed from a verb (6)
I believe the answer is:
gerund
'noun formed from a verb' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for gerund that I've seen before include "Verb form functioning as a noun" , "Verb form used as a noun" , "Verbal noun ending in 'ing'" , "Noun formed from a verb - red gun (anag)" , "Noun formed from a verb -- nudger (anag)" .)