Joust (4)
I believe the answer is:
tilt
'joust' is the definition.
(I know that joust can be written as tilt)
This is all the clue.
(Other definitions for tilt that I've seen before include "Stab" , "Slope; use a lance in jousting" , "Joust; bias" , "Engage in a medieval joust - lean" , "Inclination, joust" .)