Electric feature of extramarital affairs (4)

I believe the answer is:

tram

'electric' is the definition.
(thesaurus)

'feature of extramarital affairs' is the wordplay.
'feature of' says the answer is hidden in the clue.
'TRAM' is hidden in the letters of 'extramarital affairs'.

(Other definitions for tram that I've seen before include "Streetcar" , "An early form of Luas in Dublin transport" , "Bus on rails" , "Take it to the mart" , "Electrically driven transport" .)

I've seen this clue in the Evening Standard.

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