Gospel writer is one suitable for swindling (4)
I believe the answer is:
mark
'gospel writer' 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 mark that I've seen before include "Note - evangelist" , "Point; former coin" , "Characteristic" , "Brand - old German currency" , "follower of Jesus" .)