Army team’s hired transport (4)
I believe the answer is:
taxi
'hired transport' is the definition.
'army team's' is the wordplay.
'army' becomes 'ta' (abbreviation for Territorial Army).
'team' becomes 'xi' (eleven, a football team).
'ta'+'xi'='TAXI'
(Other definitions for taxi that I've seen before include "Transport for hire" , "Handgun" , "type of vehicle" , "Hired vehicle" , "Part of fleet" .)