What unites neo-Marxists? (6)
I believe the answer is:
hyphen
I'm afraid I can't even guess how this answer relates to the clue.
Can you help me to learn more?
(Other definitions for hyphen that I've seen before include "Stroke between syllables or words" , "A horizontal word joiner" , "Horizontal words joiner" , "Mark between parts of a compound word" , "Word-joining mark" .)