A lover of insincerity (5)
I believe the answer is:
flirt
This could be a double definition.
'a lover' is the first definition.
The definition and answer can be both people as well as being singular nouns.
Maybe you can see an association between them that I don't see?
'insincerity' is the second definition.
Although both the answer and definition are singular nouns, I don't understand how one could define the other.
'of' is the link.
Can you help me to learn more?
(Other definitions for flirt that I've seen before include "Engage lightheartedly in amorous banter" , "Play at courtship" , "Saucy girl" , "Be playfully amorous" , "Coquet" .)