Leave, accompanied by X (8)
I believe the answer is:
withdraw
'leave' is the definition.
(I know that withdraw is a more specific form of the action retire)
'accompanied by x' is the wordplay.
'accompanied by' becomes 'with' (I've seen this before).
'x' becomes 'draw' (I can't explain this - if you can you should give a lot more credence to this answer).
'with'+'draw'='WITHDRAW'
Can you help me to learn more?
(Other definitions for withdraw that I've seen before include "Scratch" , "Bow out, retreat" , "Take, go, back" , "depart?" , "Remove, take away" .)