Deer getting frisky with sun bears (7)
I believe the answer is:
endures
'bears' is the definition.
('endure' can be a synonym of 'bear')
'deer getting frisky with sun' is the wordplay.
'getting frisky with' is an anagram indicator.
'deer' mixed up with 'sun' gives 'ENDURES'.
(Other definitions for endures that I've seen before include "Lasts or puts up with" , "Bears" , "Tolerates" , "Suffers or lasts" , "Ensured (anag.)" .)