A politician greeting British Scot is a cold-blooded creature (9)
I believe the answer is:
amphibian
'cold-blooded creature' is the definition.
'amphibian' can be an answer for 'creature' (amphibian is a kind of animal). I'm not sure about the 'cold-blooded' bit.
'a politician greeting british scot' is the wordplay.
'politician' becomes 'MP' (Member of Parliament).
'greeting' becomes 'hi' (hi is a kind of greeting).
'british' becomes 'b' (abbreviation e.g. in BBC).
'scot' becomes 'ian' (Scottish given name).
'a'+'mp'+'hi'+'b'+'ian'='AMPHIBIAN'
'is a' is the link.
Can you help me to learn more?
(Other definitions for amphibian that I've seen before include "Animal able to live in both land and water" , "Frog for one" , "Animal that lives on land and in water" , "aircraft" , "Eg, newt or toad" .)