Smooth operator taking one in - I'll find belief in odd places (9)
I believe the answer is:
plausible
'smooth' is the definition.
(thesaurus)
I don't understand the rest of the clue.
Can you help me to learn more?
(Other definitions for plausible that I've seen before include "Seemingly true" , "easy to swallow" , "Credible" , "Reasonable on the face of it" , "False but sounding true" .)