I have a question regarding the use of hyphens in words with certain prefixes, for. For example:,
Neo-Nazism
Neo-Confucianism
Neo-liberal
Areare words with a hyphen, but:
Neoplatonism
Neocolonialism
are words without hyphens. I'm especially confused with neo-Confucianismneo-Confucianism and neoplatonism;neoplatonism: one contains a hyphen and a capital letter and the other doesn't.
Is there a specific rule for hyphens in words with prefixes or is it purely arbitrary?