Came struggling to make summit (4)
I believe the answer is:
acme
'summit' is the definition.
(synonyms)
'came struggling' is the wordplay.
'struggling' is an anagram indicator (the letters struggle or wriggle into a new form).
'came' with letters rearranged gives 'ACME'.
'to make' is the link.
(Other definitions for acme that I've seen before include "crisis in history" , "Height of excellence" , "high peak" , "Point of perfection, apex" , "High point of excellence" .)