Stepped on a split-ended stick (4)
I believe the answer is:
trod
'stepped' is the definition.
('tread' can be a synonym of 'step')
'on a split-ended stick' is the wordplay.
'on' is a charade indicator (letters next to each other).
'a split-ended' becomes 't' (I can't explain this - if you can you should give a lot more credence to this answer).
'stick' becomes 'rod' (I've seen this before).
't' put next to 'rod' is 'TROD'.
Can you help me to learn more?
(Other definitions for trod that I've seen before include "Walked (on something)" , "Walked heavily, put foot down" , "start making wine" , "Crushed (grapes) by foot" , "Pressed (something) down with the feet" .)