Deep professional discovered (8)
I believe the answer is:
profound
'deep' is the definition.
(synonyms)
'professional discovered' is the wordplay.
'professional' becomes 'pro' (abbreviation).
'discovered' becomes 'found' (to discover is to find).
'pro'+'found'='PROFOUND'
(Other definitions for profound that I've seen before include "deeply intellectual" , "Extensive" , "Overpowering" , "anything but superficial" , "showing great knowledge" .)