Powerful info during company time (6)
I believe the answer is:
cogent
'powerful' is the definition.
(thesaurus)
'info during company time' is the wordplay.
'info' becomes 'gen' (gen is a kind of info).
'during' means one lot of letters goes inside another.
'company' becomes 'co' (abbreviation).
'time' becomes 't'.
'co'+'t'='cot'
'gen' put within 'cot' is 'COGENT'.
(Other definitions for cogent that I've seen before include "'Powerfully persuasive, argument say (6)'" , "Well-reasoned" , "Clearly argued" , "Clear, logical and convincing" , "Strong" .)