Wheels are his sole means of locomotion (6,6)
I believe the answer is:
roller skater
'wheels are his sole means' is the definition.
The definition suggests a singular noun which matches the answer.
'locomotion' is the wordplay.
I cannot really see how this works, but
'locomotion' could be 'roll' (roll is a kind of locomotion) and 'roll' is found in the answer.
This explanation may well be incorrect...
'of' is the link.
Can you help me to learn more?
(Other definitions for roller skater that I've seen before include "One wearing boots with wheels" , "Slider on small wheels" .)