Admits every other one employed is abandoned (7)
I believe the answer is:
disused
'abandoned' is the definition.
(disused can mean abandoned or no longer in use)
'admits every other one employed is' is the wordplay.
'admits' is an insertion indicator.
'every other' becomes 'd' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'one employed' becomes 'used' (I've seen this before).
'd'+'used'='dused'
'dused' enclosing 'is' is 'DISUSED'.
Can you help me to learn more?
(Other definitions for disused that I've seen before include "Derelict" , "Neglected" , "No longer observed or practised" , "empty" , "No longer operated" .)