Elderly are proceeding cautiously about publicity, being nervous (2,6,7)
I believe the answer is:
no spring chicken
'elderly are proceeding cautiously' is the definition.
I know nothing about this answer so I cannot judge whether it can be defined by this definition.
'publicity being nervous' is the wordplay.
I cannot really see how this works, but
'publicity' could be 'pr' (public relations) and 'pr' is present in the answer.
'being' could be 'chick' (chick is a kind of being) and 'chick' is present in the answer.
This explanation may well be incorrect...
'about' acts as a link.
Can you help me to learn more?
(Other definitions for no spring chicken that I've seen before include "Veteran" , "unseasoned meat, might you say?" , "old?" , "not young any more" , "One who's seasoned" .)