Beginning of end of Himalayan climb (7)
I believe the answer is:
nascent
'beginning' is the definition.
(thesaurus)
'end of himalayan climb' is the wordplay.
'end of' indicates one should take the final letters.
'climb' becomes 'ascent' ('ascent' can be a synonym of 'climb').
The last letter of 'himalayan' is 'n'.
'n'+'ascent'='NASCENT'
'of' is the link.
(Other definitions for nascent that I've seen before include "awakening" , "just coming into effect" , "Starting to develop" , "not yet mature" , "Starting existence" .)