Hardy sort of snake (5)
I believe the answer is:
hydra
'snake' is the definition.
(I know that snake can be written as Hydra)
'hardy sort' is the wordplay.
'sort' indicates an anagram.
'hardy' anagrammed gives 'HYDRA'.
'of' acts as a link.
(Other definitions for hydra that I've seen before include "Mythological monster with nine heads" , "Greek island" , "Mythical many-headed snake" , "Nine-headed monster killed by Hercules" , "Water monster" .)