Tricks mum by returning cigarette (5)
I believe the answer is:
magic
'tricks' is the definition.
(I've seen this before)
'mum by returning cigarette' is the wordplay.
'mum' becomes 'ma' (ma can mean mother).
'by' says to put letters next to each other.
'returning' says the letters should be written backwards.
'cigarette' becomes 'cig' (short for cigarette).
'cig' in reverse letter order is 'gic'.
'ma'+'gic'='MAGIC'
(Other definitions for magic that I've seen before include "Great" , "Conjuror's art" , "Entertainment at a children's party?" , "Tricks" , "Wizardry - wizard!" .)