Colour of extremely comfy afghan (4)
I believe the answer is:
cyan
'colour' is the definition.
(greenish blue colour)
'extremely comfy afghan' is the wordplay.
'extremely' suggests removing the centre (only the extremes of the word are used).
'afghan' becomes 'an' (I can't explain this - if you can you should believe this answer much more).
'comfy' with its middle taken out is 'cy'.
'cy'+'an'='CYAN'
'of' acts as a link.
Can you help me to learn more?
(Other definitions for cyan that I've seen before include "Primary blue colour in printing" , "Printer's blue" , "Bluish green" , "Greenish-blue colour complementary to red" , "Bluish-green" .)