Capable of high speed — or not? (3-2)
I believe the answer is:
ton-up
I believe this is a double definition.
'capable of high speed' is the first definition.
(ton-up means fond of travelling at speed)
'not?' is the second definition.
(I've seen this before)
'or' acts as a link.
(Other definitions for ton-up that I've seen before include "Travelling at one hundred mph" , "fast!" , "Going at over 100mph" , "Fond of travelling at high speed" , "going quickly" .)