Terrible blow for English MP in exam (7)
I believe the answer is:
tempest
'terrible blow' is the definition.
(I've seen this before)
'english mp in exam' is the wordplay.
'english' becomes 'E' (abbreviation).
'in' is an insertion indicator.
'exam' becomes 'test' (synonyms).
'e'+'mp'='emp'
'emp' put inside 'test' is 'TEMPEST'.
'for' acts as a link.
(Other definitions for tempest that I've seen before include "A great storm of wind and rain" , "tosser!" , "Big blow" , "Shakespeare play with storm scene" , "Violent storm (created by Shakespeare?)" .)