Friendly hosts I would scare (10)
I believe the answer is:
intimidate
'scare' is the definition.
(intimidate can mean to scare)
'friendly hosts i would' is the wordplay.
'friendly' becomes 'intimate' (I've seen this before).
'hosts' means one lot of letters goes inside another (inserted letters are welcomed or hosted).
'i would' becomes 'I'd'.
'intimate' going around 'id' is 'INTIMIDATE'.
(Other definitions for intimidate that I've seen before include "Strike fear into" , "Bully" , "Threaten" , "Frighten" , "Scare" .)