Retiring poet (not a skilful writer) (7)
I believe the answer is:
drabble
'writer' is the definition.
(novelist Margaret Drabble)
'retiring poet not a skilful' is the wordplay.
'retiring' shows that the letters should be reversed in order.
'poet' becomes 'bard' (bard is a kind of poet).
'not' suggests deleting specific letters.
'skilful' becomes 'able' (I've seen this before).
'bard' back-to-front is 'drab'.
'able' with 'a' removed is 'ble'.
'drab'+'ble'='DRABBLE'
(Other definitions for drabble that I've seen before include "Margaret -, English novelist" , "Make dirty; Margaret --, author" .)