Cup of tea cold in lounge (7)
I believe the answer is:
chalice
'cup' is the definition.
(chalice is a kind of cup)
'tea cold in lounge' is the wordplay.
'tea' becomes 'cha' (cha is a type of tea).
'cold' becomes 'c' (eg on taps).
'in' is an insertion indicator.
'lounge' becomes 'lie' (I've seen this in other clues).
'c' placed within 'lie' is 'lice'.
'cha'+'lice'='CHALICE'
'of' is the link.
(Other definitions for chalice that I've seen before include "cup used in company with host" , "Wine cup used at Christian Eucharist" , "Large goblet for consecrated wine" , "Church wine cup" , "Necessity for communion" .)