Give evidence from exam if with head of year (7)
I believe the answer is:
testify
'give evidence' is the definition.
(I've seen this in another clue)
'exam if with head of year' is the wordplay.
'exam' becomes 'test' (synonyms).
'with head of' suggests taking the first letters.
The first letter of 'year' is 'y'.
'test'+'if'+'y'='TESTIFY'
'from' is the link.
(Other definitions for testify that I've seen before include "sworn" , "Affirm (on oath)" , "Bear witness in court" , "take the stand" , "Give evidence in court" .)