Got over anaesthetic at the same time (8)
I believe the answer is:
together
'at the same time' is the definition.
(synonyms)
'got over anaesthetic' is the wordplay.
'over' shows that the letters should be reversed in order.
'anaesthetic' becomes 'ether' (ether is a kind of anaesthetic).
'got' backwards is 'tog'.
'tog'+'ether'='TOGETHER'
(Other definitions for together that I've seen before include "stable" , "at the same time" , "One with another, simultaneously" , "In each other's company" , "United; in agreement" .)