Considered motorway second-hand (5)
I believe the answer is:
mused
'considered' is the definition.
The definition and answer can be both related to thinking as well as being past participle verbs.
Perhaps there's a link between them I don't understand?
'motorway second-hand' is the wordplay.
'motorway' becomes 'M' (as in motorway names - M1, M4 etc).
'second hand' becomes 'used' (second hand can mean previously owned or used).
'm'+'used'='MUSED'
Can you help me to learn more?
(Other definitions for mused that I've seen before include "Reflected or pondered" , "Was deep in thought" , "Reflected in silence" , "Thought (to oneself)" , "Contemplated" .)