Hold tightly (to) (5)
I believe the answer is:
cling
'hold tightly to' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for cling that I've seen before include "Adhere, hold tight" , "Be emotionally over-dependent" , "Hold on tightly, be dependent" , "Grasp urgently" , "Stick - tinkle" .)