Such old jokes may get a frosty reception (5)
I believe the answer is:
hoary
'such old' is the definition.
'hoary' can be an answer for 'old' (similar in meaning). I'm not certain of the 'such' bit.
I cannot understand how the rest of the clue works.
Can you help me to learn more?
(Other definitions for hoary that I've seen before include "White or grey with age" , "Grizzled or frosted" , "Venerably grey" , "Grey haired; old (joke)" , "Frosty" .)