Information appeal before writer's case (8)
I believe the answer is:
genitive
'case' is the definition.
(the genitive case in grammar)
'information appeal before writer's' is the wordplay.
'information' becomes 'gen' (gen can informally mean information).
'appeal' becomes 'it' ('it' can mean something attractive or appealing).
'before' means one lot of letters go next to another.
'writer's' becomes 'i've' ('I have' can refer to the person writing).
'gen'+'it'+'ive'='GENITIVE'
(Other definitions for genitive that I've seen before include "This case shows possession" , "(In grammar) the possessive case" .)