Poet's boring in retirement (4)
I believe the answer is:
bard
'poet's' is the definition.
(bard is a kind of poet)
'boring in retirement' is the wordplay.
'boring' becomes 'drab' (I've seen this in another clue).
'in retirement' shows that the letters should be reversed in order (retire can mean to go back or backwards).
'drab' back-to-front is 'BARD'.
(Other definitions for bard that I've seen before include "Eisteddfod winner" , "Poet - prophet" , "Traditional poet" , "Epic poet" , "A lyric poet" .)