Pack including second two cards — one's worn (7,6)
'one's worn' is the definition.
'pack including second two cards' is the wordplay.
'two cards' can mean two substitutions for 'card'.
'pack' becomes 'set'.
'including' indicates putting letters inside.
'second' becomes 'mo' (both are short periods of time).
'card' becomes 'king' (king is a kind of card**).
'card' becomes 'jack' (type of playing card).
'set' placed around 'mokingjack' is 'SMOKING JACKET'.
(Other definitions for smoking jacket that I've seen before include "piece of attire" , "Garment for puffers" , "Soft short coat for a man - Jack's gnome kit (anag)" .)
'worn' is the definition.
Both the definition and answer are adjectives. Perhaps they are linked in a way I don't understand?
'pack including second two cards one's' is the wordplay.
I cannot really understand how this works, but
'second' could be 'mo' (both are short periods of time) and 'mo' is present in the answer.
'one' could be 'i' (Roman numeral) and 'i' is found within the answer.
This explanation may well be incorrect...
(Other definitions for smoking that I've seen before include "Using tobacco" , "unhealthy habit" , "Having a cigarette" , "Emitting a cloud of gas" , "Puffing a fag" .)