Crawl up and run across (4)
I believe the answer is:
meet
'run across' is the definition.
(synonyms)
I don't understand how the rest of the clue works.
Can you help me to learn more?
(Other definitions for meet that I've seen before include "Come across" , "Confront" , "Come face to face with - it is proper" , "Happen upon" , "assembly at hunt" .)