Peninsula: sea freezing cold (5)
I believe the answer is:
medoc
'peninsula' is the definition.
I know nothing about this answer so I can't tell whether it can be defined by this definition.
'sea freezing cold' is the wordplay.
I cannot really see how this works, but
'sea' could be 'med' (short for Mediterranean) and 'med' is present in the answer.
'freezing' could be 'oc' (zero degrees Celsius) and 'oc' is present in the answer.
This accounts for all the letters.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for medoc that I've seen before include "Wine-growing area" , "region of France" , "Type of wine" , "that's regularly drunk?" , "Red wine from southwest France" .)