Relative cut by retired writer (6)
I believe the answer is:
nephew
'relative' is the definition.
(nephew is a kind of relative)
'cut by retired writer' is the wordplay.
'cut' becomes 'hew' (I've seen this before**).
'by' says to put letters next to each other.
'retired' says the letters should be written backwards.
'writer' becomes 'pen' (I've seen this before).
'pen' backwards is 'nep'.
'hew' put after 'nep' is 'NEPHEW'.
(Other definitions for nephew that I've seen before include "Male relative" , "Sibling's son" , "A sibling's child" , "Has a duty (to do something)" , "Sister's son" .)