Banish some nervous tension (4)
I believe the answer is:
oust
'banish' is the definition.
(thesaurus)
'some nervous tension' is the wordplay.
'some' indicates the answer is hidden within the clue (some of the parts of the word are used).
'OUST' can be found hidden inside 'nervous tension'.
(Other definitions for oust that I've seen before include "Get rid of" , "Send packing" , "Expel from office or position" , "Turn out" , "Remove from a position or office" .)