Lmfaoooooo it's OK ik it cuz of my friends, I think the dictionary will explain it better so I copied.
"a word used when you agree with something; or when you want to recognize someone for being themselves, i.e. courageous and unique or not caring what others think."
It just means I really agree with you and your opinion honestly.
Have a great day ヾ(☆▽☆)
it basically means you really agree with someone’s opinion. as a millennial, I will try to explain in gen z terms: when Olivia Rodrigo gave out birth control at her concerts she was based af because supporting women’s reproductive rights is based (unfortunately she caved to pushback). Or if someone hates pineapple pizza and you do too, you would say they’re based
i hope doyoon tops the sunbae