Doing nothing right in an examination (2,4)
I believe the answer is:
at rest
'doing nothing' is the definition.
(I've seen this in another clue)
'right in an examination' is the wordplay.
'right' becomes 'r' (common abbreviation).
'in' means one lot of letters goes inside another.
'an' becomes 'a'.
'examination' becomes 'test' (synonyms).
'a'+'test'='atest'
'r' going into 'atest' is 'AT REST'.
(Other definitions for at rest that I've seen before include "Treats (anag.)" , "Immobile" , "Still" , "late" , "In relaxed state, perhaps dead" .)