Advert covering e-cigarette? (6)
I believe the answer is:
reefer
'advert covering e-cigarette?' is the definition.
Although both the answer and definition are singular nouns, I don't see how they can define each other.
'advert covering e-cigarette?' is the wordplay.
'advert' becomes 'refer' (I've seen this in another clue).
'covering' is an insertion indicator.
'e-cigarette?' becomes 'e' (this might be a standard abbreviation I've not previously seen).
'refer' placed around 'e' is 'REEFER'.
(Other definitions for reefer that I've seen before include "drugged cigarette" , "A wool jacket; a spliff" , "Type of jacket - smoke" , "Warm jacket - cannabis cigarette" , "Midshipman (sl.)" .)