Advanced group for skilful person, ... (5)
I believe the answer is:
adept
'skilful person' is the definition.
'advanced group' is the wordplay.
'advanced' becomes 'a'.
'group' becomes 'dept' (abbreviation for department).
'a'+'dept'='ADEPT'
'for' acts as a link.
(Other definitions for adept that I've seen before include "Having the skill required" , "Taped (anag.)" , "Very skilled person" , "Dexterous" , "One very skilled at work" .)