Shade of most interest (4)
I believe the answer is:
tint
'shade' is the definition.
(I know that shade is a type of shade)
'of most interest' is the wordplay.
'of' indicates the answer is hidden within the clue.
'TINT' is hidden within 'most interest'.
(Other definitions for tint that I've seen before include "A slighth shade of colour" , "Shade; colour slightly" , "'Shade, tone (4)'" , "A slight shade of colour" , "(Softer variety of) colour" .)