Lost and estranged lover can empty closet (7)
I believe the answer is:
extinct
'lost' is the definition.
(thesaurus)
'estranged lover can empty closet' is the wordplay.
'estranged lover' becomes 'ex' (I can't justify this - if you can you should give a lot more credence to this answer).
'can' becomes 'tin' (both are metal containers).
'empty' says to hollow out the word (remove centre letters).
'closet' with its middle taken out is 'ct'.
'ex'+'tin'+'ct'='EXTINCT'
'and' is the link.
Can you help me to learn more?
(Other definitions for extinct that I've seen before include "No linger in existence" , "No longer in existence" , "Permanently inactive" , "Ended" , "No longer burning" .)