Do laborious Hindi grammatical cases (7)
I believe the answer is:
shindig
'do' is the definition.
(I've seen this before)
'laborious hindi grammatical cases' is the wordplay.
'cases' indicates a hidden word.
'SHINDIG' is hidden in the letters of 'laborious hindi grammatical'.
(Other definitions for shindig that I've seen before include "Lively party, knees-up" , "Lively celebration (informal)" , "commotion" , "Rumpus" , "wild party" .)