Paper's fund for something relatively dark (7)
I believe the answer is:
sunspot
'something relatively dark' is the definition.
(a relatively dark spot visible on the sun)
'paper's fund' is the wordplay.
'paper's' becomes 'suns' (The Sun, UK newspaper).
'fund' becomes 'pot' (pot can mean a shared fund).
'suns'+'pot'='SUNSPOT'
'for' acts as a link.
(Other definitions for sunspot that I've seen before include "warm place" , "Dark cool patch on the surface of our nearest star" , "holiday resort" , "cause of magnetic storm" , "Solar cool patch" .)