Convincing the company guy! (6)
I believe the answer is:
cogent
'convincing' is the definition.
(similar in meaning)
'company guy' is the wordplay.
'company' becomes 'co' (abbreviation).
'guy' becomes 'gent' (I've seen this in another clue).
'co'+'gent'='COGENT'
'the' is the link.
(Other definitions for cogent that I've seen before include "Forceful and to the point" , "Compelling or convincing" , "Convincingly argued" , "'Powerfully persuasive, argument say (6)'" , "Clearly argued" .)