Cheer as story is rejected by Head of Ethics (5)
I believe the answer is:
elate
'cheer' is the definition.
(I've seen this in other clues)
'story is rejected by head of ethics' is the wordplay.
'story' becomes 'tale' ('tale' can be a synonym of 'story').
'is rejected' shows that the letters should be reversed in order.
'by' says to put letters next to each other.
'head of' indicates taking the first letters.
The first letter of 'ethics' is 'e'.
'tale' in reverse letter order is 'elat'.
'elat'+'e'='ELATE'
'as' is the link.
(Other definitions for elate that I've seen before include "Uplift (mood)" , "Inspirit, make exultant" , "Exhilarate, put in high spirits" , "Doctor suitor to Anne Page (MWOW)" , "Encourage" .)