Hold off with fencing sword mostly grasped with both hands (5)
I believe the answer is:
repel
'hold off' is the definition.
(I've seen this before)
I don't understand how the remainder of the clue works.
Can you help me to learn more?
(Other definitions for repel that I've seen before include "Drive back or disgust" , "Be effective in controlling" , "give you the creeps" , "'Drive back, repulse (5)'" , "Reject" .)