Old male writer taking American passenger vehicle (7)
I believe the answer is:
omnibus
'passenger vehicle' is the definition.
(I've seen this before)
'old male writer taking american' is the wordplay.
'old' becomes 'o' (common abbreviation eg in OE for Old English).
'male' becomes 'm' (common abbreviation).
'writer' becomes 'nib' (something which writes).
'taking' means one lot of letters go next to another.
'american' becomes 'us' (abbreviation for United States).
'o'+'m'+'nib'+'us'='OMNIBUS'
(Other definitions for omnibus that I've seen before include "public service" , "form of transport" , "Anthology" , "Carrier" , "Compendium volume" .)