"Fluent" has a rather vague definition, but the word root means "flowing" (like a river) - if you can speak a natural language in proper idioms without pauses in the wrong places to look for or translate words, you're fluent. "Conversant" is a rather lower standard meaning that you can have a conversation in the language and both understand and be understood.

Same here. I would never call myself fluent in Spanish, but then I've seen people on my level or worse who do and it's frustrating. I've seen plenty of similar arguments online about what it means to be fluent.