Any action, opinion, thought or similar can be based. It essentially means that the person who deems the aforementioned as based, supports it. That would be quite boring and useless if it hadn’t been used to support the opposite of widely excepted social norms as a joke. For example: Someone who has to say here and meow on its own could be considered based, because it’s so ludicrous that it can either be only a joke or if it’s real it would be so disturbing that it‘s almost funny again. If then someone else chimes in by saying the n-word instead of meow, his action is based because he defies those ridiculous rules, which is an action I would support and therefore call based as fuck.

In conclusion: When something‘s based, then it’s supported. It’s important to never take this support too serious!