You heard dram’s swallowed hot, not cool (5)
I believe the answer is:
unhip
'not cool' is the definition.
(I've seen this in another clue)
'you heard dram's swallowed hot' is the wordplay.
'you heard' becomes 'U' (homophone of 'you').
'dram's swallowed' becomes 'n' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'hot' becomes 'hip' (both can mean fashionable or trendy).
'u'+'n'+'hip'='UNHIP'
Can you help me to learn more?
(Other definitions for unhip that I've seen before include "square" , "uncool" , "Not cool" .)