Prone to deceit? (5)
I believe the answer is:
lying
'prone' is the definition.
(I've seen this before)
I don't understand how the remainder of the clue works.
Can you help me to learn more?
(Other definitions for lying that I've seen before include "Deceitful" , "Not being disturbed" , "So one can't stand" , "telling stories" , "Flat" .)