Note kittens glisten (7)
I believe the answer is:
glitter
'glisten' is the definition.
(I know that glisten can be written as glitter)
'note kittens' is the wordplay.
'note' becomes 'g' (musical note).
'kittens' becomes 'litter' (I've seen this before).
'g'+'litter'='GLITTER'
(Other definitions for glitter that I've seen before include "Shine brightly, coldly" , "Sparkling decoration" , "Gleam" , "Are bright" , "Showy decoration" .)