Communicate the writer's function (6)
I believe the answer is:
impart
'communicate' is the definition.
(impart can mean to communicate or pass on)
'writer's function' is the wordplay.
'writer's' becomes 'I'm' ('I am' referring to the writer of the clue).
'function' becomes 'part' (synonyms).
'im'+'part'='IMPART'
'the' acts as a link.
(Other definitions for impart that I've seen before include "Divulge about armpit" , "Give - convey" , "Give - tell" , "Make known, relate" , "Communicate (information)" .)