Uneven; jolting (5)
I believe the answer is:
bumpy
I believe this clue is a double definition.
'uneven' is the first definition.
(I've seen this before)
'jolting' is the second definition.
(synonyms)
(Other definitions for bumpy that I've seen before include "Jolty" , "Not even" , "Rough - turbulent" , "affected by air pockets" , "Uneven (surface); jolting" .)