A shade old to enjoy existence to the full (5)
I believe the answer is:
'a shade' is the definition.
(I know that olive is a type of green)
I don't understand the remainder of the clue.
Can you help me to learn more?
(Other definitions for olive that I've seen before include "Greyish-green; fruit" , "One [TYPE OF TREE] is from the Mediterranean" , "Cocktail fruit" , "This branch is offered to show peace" , "A Med. fruit-tree" .)