just because, even if, even though
Informal Form +
Attaches to the informal or plain form of a sentence to mean 'just because' or 'even if'. It introduces a reason for an action or idea, and is typically followed by a clause expressing disapproval, a warning, or a statement that a certain conclusion does not necessarily follow.
Verb (Informal Form) +
Used with the informal form of a verb, such as dictionary form or plain past form, to express that the action is not a sufficient reason to justify the resulting action or assumption.
疲れた
Just because you are tired, you must not give up.
い-Adjective (Informal Form) +
Attaches directly to the informal form of an い-Adjective.
安い
Just because it is cheap, it is not good to buy a lot.
な-Adjective + だ
When used with a な-Adjective, the informal copula だ must be added before
便利だ
Just because it is convenient, it is not good to use it every day.
Noun + だ
When used with a Noun, the informal copula だ must be added before
日曜日だ
Just because it is Sunday, it does not mean I can rest.
This grammar point is almost always followed by a negative expression, a warning, or a phrase stating that something should not be done or is not necessarily true. It carries a strong nuance of disapproval toward jumping to conclusions based solely on the stated reason.