A lack of effort getting fifth grades, reportedly (4)
I believe the answer is:
ease
'a lack of effort' is the definition.
'fifth grades reportedly' is the wordplay.
'fifth grades' becomes 'es' (E is the fifth grade in some exams).
'reportedly' shows a homophone (sound like).
'es' sounds like 'EASE'.
'getting' is the link.
(Other definitions for ease that I've seen before include "Lessen intensity" , "Assuage" , "Leisure, comfort" , "Lack of worry or agitation" , "Make comfortable" .)