Like crab that's cold? (5)
I believe the answer is:
nippy
'that's cold?' is the definition.
('nippy' can be similar in meaning to 'cold')
I cannot understand how the rest of the clue works.
Can you help me to learn more?
(Other definitions for nippy that I've seen before include "Fast - cold" , "Quickly-moving" , "like the wind?" , "Sharp" , "brisk" .)