Almost everyone unenthusiastic about hot drink (7)
I believe the answer is:
alcohol
'drink' is the definition.
(alcohol is a kind of drink)
'almost everyone unenthusiastic about hot' is the wordplay.
'almost' means to remove the last letter (most of the word but not all of it).
'everyone' becomes 'all' (all people).
'unenthusiastic' becomes 'cool' (I've seen this before).
'about' means one lot of letters goes inside another.
'hot' becomes 'h' (abbreviation eg on taps).
'all' with its final letter taken off is 'al'.
'cool' going around 'h' is 'cohol'.
'al'+'cohol'='ALCOHOL'
(Other definitions for alcohol that I've seen before include "The hard stuff" , "Drug" , "It can make one merry" , "Booze" , "Intoxicating substance" .)