Its tip, you see, is not a hot one! (7)
I believe the answer is:
iceberg
'a hot one' is the definition.
Although both the answer and definition are singular nouns, I can't understand how they can define each other.
'its tip you see is not' is the wordplay.
I cannot really understand how this works, but
'see' could be 'c' (the word for the letter, according to Chambers) and 'c' is located in the answer.
'is' could be 'be' and 'be' is present in the answer.
This may be the basis of clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for iceberg that I've seen before include "Arctic shipping hazard" , "Calf's parent" , "Maritime danger, mostly underwater" , "last scene of Titanic" , "smash hit in Titanic?" .)