Sierra tailgates Clio maybe out of motorway services (4)
I believe the answer is:
uses
'sierra tailgates' is the definition.
Although both the answer and definition are verbs in their -s form, I cannot see how one could define the other.
'clio maybe out of motorway services' is the wordplay.
'clio maybe' becomes 'muse' (Clio is the muse of history in Greek mythology).
'out of' suggests deleting specific letters.
'motorway' becomes 'M' (as in motorway names - Ms, M4 etc).
'services' becomes 's' (this could be a standard abbreviation of which I'm unaware).
'muse' with 'm' taken out is 'use'.
'use'+'s'='USES'
Can you help me to learn more?
(Other definitions for uses that I've seen before include "Puts to a particular purpose" , "Employs" , "Takes (drugs)" , "Purposes; consumes" , "Employments" .)