We would embrace tightly in marriage (7)
I believe the answer is:
wedlock
'marriage' is the definition.
(I know that marriage can be written as wedlock)
'we would embrace tightly' is the wordplay.
'we would' becomes 'we'd'.
'embrace tightly' becomes 'lock' (locking is a kind of embracing. I am not sure about the 'tightly' bit.).
'wed'+'lock'='WEDLOCK'
'in' acts as a link.
Can you help me to learn more?
(Other definitions for wedlock that I've seen before include "A state of union" , "Matrimony" , "The married state - throw away the key" , "Marital state" , "State of marriage" .)