Skilled fellow left out of myth (4)
I believe the answer is:
able
'skilled' is the definition.
(I've seen this before)
'fellow left out of myth' is the wordplay.
'fellow' becomes 'F' (abbreviation - of a society etc.).
'left out of' is a deletion indicator.
'myth' becomes 'fable' (I've seen this before).
'fable' with 'f' taken away is 'ABLE'.
(Other definitions for able that I've seen before include "Having the power, skill or means (to do something)" , "... was I ere I saw Elba (palindrome)" , "Well-equipped" , "Having considerable skill" , "With the required capacities" .)