Jellystone Park bear (4)
I believe the answer is:
yogi
'jellystone park bear' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for yogi that I've seen before include "philosophy student" , "Hindu mystic" , "-- Bear, cartoon character" , "Practising philosopher" , "Cartoon bear (who has mastered Hindu philosophy?)" .)