Bind firmly (4)
I believe the answer is:
lash
'bind firmly' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for lash that I've seen before include "Beat; fasten with cord" , "Whip with a sharp blow" , "over the eye" , "Flexible strip of a whip" , "Hit with a whip" .)