just because; even if; even though
Used to deny a natural expectation: 'just because A, it doesn't mean B'. Often followed by a negative or limiting statement.
Just because you have money doesn't mean you're happy.
Even if you're busy, skipping meals is not good.
Combination of the reason particle から, the quotative particle と, and the te-form of 言う (to say). Literally 'even if one says because...', it developed into a fixed expression for denying a natural consequence.