Firm facing endless shame to go under? (3,2)
I believe the answer is:
cop it
'go under?' is the definition.
(both can mean to be punished or convicted)
'firm facing endless shame' is the wordplay.
'firm' becomes 'co' (a firm is a company).
'facing' says to put letters next to each other.
'endless' means to remove the last letter.
'shame' becomes 'pity' (synonyms).
'pity' with its last letter taken off is 'pit'.
'co'+'pit'='COP IT'
'to' acts as a link.
(Other definitions for cop it that I've seen before include "Be punished" , ""get in loads of trouble!"" , "Suffer the consequences!" , "Get into trouble; be killed" , "Get it in the neck" .)