Cold one containing ice-cream? (4)
I believe the answer is:
cone
'ice-cream?' is the definition.
(I've seen this in other clues)
'cold one' is the wordplay.
'cold' becomes 'C' (eg on taps).
'c'+'one'='CONE'
'containing' acts as a link.
(Other definitions for cone that I've seen before include "Circular pyramid" , "Dry fruit of many evergreen trees, say pine" , "Road furniture!" , "99, maybe" , "Ice-cream cornet" .)