Struggling writer not unknown to importune newspaper boss (4-7)
I believe the answer is:
hard-pressed
'struggling writer' is the definition.
'hard-pressed' can be an answer for 'struggling' (both can mean in difficulty or under stress). I am not sure about the 'writer' bit.
'not unknown to importune newspaper boss' is the wordplay.
'not unknown' becomes 'hard' (I can't justify this - if you can you should believe this answer much more).
'to importune' becomes 'press' (both can mean to beg or harass).
'newspaper boss' becomes 'ed' (I've seen this in other clues).
'hard'+'press'+'ed'='HARD-PRESSED'
(Other definitions for hard-pressed that I've seen before include "Closely pursued; in difficulties" , "In difficulties or tension" .)