Employee who's lacking secretarial skill (9)
I believe the answer is:
shorthand
'secretarial skill' is the definition.
Although both the answer and definition are singular nouns, I can't see how one could define the other.
'employee who's lacking' is the wordplay.
I cannot really understand how this works, but
'employee' could be 'hand' (hand is a kind of employee) and 'hand' is located in the answer.
'lacking' could be 'short' (to be short something is to lack it) and 'short' is present in the answer.
This accounts for all the letters.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for shorthand that I've seen before include "Speed writing" , "Aid to taking dictation" , "Pitman's invention" , "Recorded words" , "Method of abbreviated writing" .)