Hue of most interest (4)
I believe the answer is:
tint
'hue' is the definition.
(tint is a kind of colour)
'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 "Quality of colour" , "Hue, shade" , "work for coiffeuse?" , "(Softer variety of) colour" , "'Shade, tone (4)'" .)