Poorly applied sinus gel leads to unsightliness (8)
I believe the answer is:
ugliness
'unsightliness' is the definition.
The definition and answer can be both human attributes as well as being singular nouns.
Maybe you can see a link between them that I can't see?
'poorly applied sinus gel leads' is the wordplay.
'sinus gel' can be anagrammed to 'UGLINESS'.
Though, I am not sure how this is indicated.
'to' acts as a link.
Can you help me to learn more?
(Other definitions for ugliness that I've seen before include "Hideous aspect" , "Unattractiveness" , "Repulsive quality" , "Complete lack of beauty" , "Unattractive quality" .)