Commercial vehicle acquires seal for promotion (11)
I believe the answer is:
advancement
'for promotion' is the definition.
(synonyms)
'commercial vehicle acquires seal' is the wordplay.
'commercial' becomes 'ad' (abbreviation for advertisement).
'vehicle' becomes 'van' (type of vehicle).
'acquires' is a charade indicator (letters next to each other).
'seal' becomes 'cement' (I've seen this before).
'ad'+'van'+'cement'='ADVANCEMENT'
(Other definitions for advancement that I've seen before include "making progress" , "getting on" , "Promotion in rank" , "headway" , "Process of developing" .)