Last of shade still protecting excessively hot canine (3,5)
I believe the answer is:
eye tooth
'canine' is the definition.
(I've seen this before)
'last of shade still protecting excessively hot' is the wordplay.
'last of' says to take the final letters.
'still' becomes 'yet' ('yet' can be a synonym of 'still'**).
'protecting' indicates putting letters inside.
'excessively' becomes 'too' ('too' can be a synonym of 'excessively').
'hot' becomes 'h'.
The final letter of 'shade' is 'e'.
'yet' enclosing 'too' is 'yetoot'.
'e'+'yetoot'+'h'='EYE-TOOTH'
(Another definition for eye tooth that I've seen is " Canine".)