It' hot to the tongue and cold to the ear (6)
I believe the answer is:
chilli
'it' hot to the tongue' is the definition.
I can't tell whether this defines the answer.
'cold to the ear' is the wordplay.
'cold' becomes 'chilly' (I've seen this before).
'to the ear' indicates a 'sounds like' (homophone) clue.
'chilly' is a homophone of 'CHILLI'.
'and' is the link.
Can you help me to learn more?
(Other definitions for chilli that I've seen before include "Hot-tasting red pepper used as relish" , "Hot stuff (though it sounds cold)" , "sort of powder" , "Hot red pepper used as seasoning" , "Give up completely" .)