Rare vacant tenancy agreement being free (7)
I believe the answer is:
release
'being free' is the definition.
(to release someone is to free them)
'rare vacant tenancy agreement' is the wordplay.
'vacant' says to hollow out the word (remove centre letters) (a vacant or emptied out form of the word).
'tenancy agreement' becomes 'lease' (agreement for leasing a property).
'rare' with its middle taken out is 're'.
're'+'lease'='RELEASE'
(Other definitions for release that I've seen before include "press announcement" , "Liberate" , "Authorise publication" , "Let go" , "put out" .)