Be emotionally over-dependent (5)
I believe the answer is:
cling
'be emotionally over-dependent' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for cling that I've seen before include "Adhere to - ring" , "Stick - tinkle" , "Clasp closely" , "have emotional attachment?" , "Hold tightly, become attached" .)