Kingpin, first and last, a very clear description of double-dealing (7)
I believe the answer is:
knavery
'clear description of double-dealing' is the definition.
Although both the answer and definition are singular nouns, I don't understand how one could define the other.
'kingpin first and last a very' is the wordplay.
'first and last' means to remove the middle letters (only the first and last letters are used).
'kingpin' with its middle taken out is 'kn'.
'kn'+'a'+'very'='KNAVERY'
Can you help me to learn more?
(Other definitions for knavery that I've seen before include "Villainy" , "Chicanery" , "fraud" , "Dishonest behaviour" , "Corrupt behaviour" .)