Seeing bears regularly going to mountain (5)
I believe the answer is:
eiger
'to mountain' is the definition.
(Swiss mountain)
'seeing bears regularly going' is the wordplay.
'regularly going' means one should take alternating letters (letters removed at regular intervals).
'seeing'+'bears'='seeingbears'
The alternate letters of 'seeingbears' are 'EIGER'.
(Other definitions for eiger that I've seen before include "Swiss mountain with a notorious north face" , "Keen" , "North wall mountain" , "Mountains in Bernese Alps" , "Mountain in the Alps" .)