Digital enhancement is cosmetic (4,7)
I believe the answer is:
nail varnish
I believe this is a double definition.
'digital enhancement' is the first definition.
(I've seen this before)
'cosmetic' is the second definition.
(nail varnish is a kind of cosmetic)
'is' acts as a link.
(Other definitions for nail varnish that I've seen before include "Substance applied to finger ends" , "Shiny fluid applied to the tips of one's digits" , "Manicurist's cosmetic lacquer" , "digital enhancement" , "Lacquer applied to the body's extremities" .)