Most endure somehow? That’s terrific (10)
I believe the answer is:
tremendous
'terrific' is the definition.
(synonyms)
'most endure somehow?' is the wordplay.
'somehow?' indicates an anagram (I've seen 'somehow' mean this).
'most'+'endure'='mostendure'
'mostendure' is an anagram of 'TREMENDOUS'.
'that's' is the link.
(Other definitions for tremendous that I've seen before include "Immense" , "Wonderful" , "Splendid!" , "Terrific" , "large" .)