Ties up and watches over aggressive dog (7)
I believe the answer is:
secures
'ties up' is the definition.
The answer and definition can be both to do with contact as well as being verbs in their -s form.
Maybe there's a link between them I don't understand?
'watches over aggressive dog' is the wordplay.
'watches' becomes 'sees' (seeing is a kind of watching).
'over' is an insertion indicator.
'aggressive dog' becomes 'cur' (I've seen this before).
'sees' enclosing 'cur' is 'SECURES'.
'and' is the link.
Can you help me to learn more?
(Other definitions for secures that I've seen before include "Makes firmly attached" , "Closes, fortifies" , "Guarantees" , "Makes safe through rescues" , "Ties down" .)