Insincere, in a way (4)
I believe the answer is:
glib
'insincere in a way' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for glib that I've seen before include "Silver-tongued" , "freedom of speech?" , "Fluent and plausible" , "Fluent but insincere" , "Slippery in speech" .)