Huge nitpicker intermittently teased (4)
I believe the answer is:
epic
'huge' is the definition.
(I've seen this before)
'nitpicker intermittently teased' is the wordplay.
'intermittently' indicates alternate letters.
'teased' indicates anagramming the letters.
The alternate letters of 'nitpicker' are 'ipce'.
'ipce' anagrammed gives 'EPIC'.
(Other definitions for epic that I've seen before include "Long poem set in nice picture" , "imposing" , "On a grand scale, maybe a poem" , "Colossal" , "Tale of heroic deeds" .)