English currently working to unseat one board (7)
I believe the answer is:
entrain
'board' is the definition.
(entraining is a kind of boarding)
'english currently working to unseat one' is the wordplay.
'english' becomes 'e' (abbreviation).
'currently working' becomes 'intrain' (in train can mean in progress).
'to unseat' suggests deleting specific letters.
'one' becomes 'i' (Roman numeral).
'intrain' with 'i' removed is 'ntrain'.
'e'+'ntrain'='ENTRAIN'
(Other definitions for entrain that I've seen before include "Get on a rail service" , "Bring about as consequence" , "Get on board railway carriages" , "board the Orient Express?" , "Sweep along" .)