Terribly bad sign for corporation? (7)
I believe the answer is:
abdomen
'corporation?' is the definition.
(I've seen this before)
'terribly bad sign' is the wordplay.
'terribly' indicates anagramming the letters.
'sign' becomes 'omen' (omen is a kind of sign).
'bad' with letters rearranged gives 'abd'.
'abd'+'omen'='ABDOMEN'
'for' acts as a link.
(Other definitions for abdomen that I've seen before include "pot" , "Region of the body between the thorax and pelvis" , "4 part of insect" , "Central region" , "Central part of the body" .)