Hapless chap playing with words, not initially clever (7)
I believe the answer is:
cunning
'clever' is the definition.
(I know that clever can be written as cunning)
'hapless chap playing with words not initially' is the wordplay.
'hapless chap' becomes 'c' (I am not sure about this - if you are sure you should believe this answer much more).
'playing with words' becomes 'punning' (a pun is a form of wordplay).
'not initially' means to remove the first letter.
'punning' with its first letter taken off is 'unning'.
'c'+'unning'='CUNNING'
Can you help me to learn more?
(Other definitions for cunning that I've seen before include "Cleverness, ingenuity" , "Clever in an underhand way" , "'Craftiness, guile (7)'" , "Clever, ingenious" , "Devious" .)