Tripped (8)
I believe the answer is:
stumbled
'tripped' is the definition.
('stumble' can be a synonym of 'trip')
This is all the clue.
(Other definitions for stumbled that I've seen before include "Lost balance in walking or speaking" , "Momentarily tripped" , "Lost one's footing" , "Missed a step and almost fell" , "Tripped, faltered" .)