Isn't worried about the colour for a moment (7)
I believe the answer is:
instant
'moment' is the definition.
(I know that moment can be written as instant)
'isn't worried about the colour' is the wordplay.
'worried' is an anagram indicator.
'about' means one lot of letters goes inside another.
'the colour' becomes 'tan' (tan is a kind of colour).
'isnt' with letters rearranged gives 'inst'.
'inst' placed around 'tan' is 'INSTANT'.
'for a' acts as a link.
(Other definitions for instant that I've seen before include "Moment - this month" , "Tick" , "Jiffy" , "Not detailed" , "Short time; immediate" .)