Refuse to show signs of old age (7)
I believe the answer is:
decline
This could be a double definition.
'refuse' is the first definition.
(I know that refuse can be written as decline)
'signs of old age' is the second definition.
'decline' can be an answer for 'age' (thesaurus). I'm not sure about the 'signs of old' bit.
'to show' acts as a link.
Can you help me to learn more?
(Other definitions for decline that I've seen before include "Refuse to accept" , "Refuse; decay" , "Dwindle" , "Start to fail" , "Become fewer; politely refuse" .)