Extremely scared around brown bear (5)
I believe the answer is:
stand
'bear' is the definition.
(bear can mean to stand or endure)
'extremely scared around brown' is the wordplay.
'extremely' says to hollow out the word (remove centre letters) (only the extremes of the word are used).
'around' is an insertion indicator.
'brown' becomes 'tan' (tan is a kind of brown).
'scared' with its middle taken out is 'sd'.
'sd' placed around 'tan' is 'STAND'.
(Other definitions for stand that I've seen before include "Decline to interfere when one should?" , "Be upright; attitude" , "principled position" , "Seek election; attitude" , "Base < put up with" .)