conjunction
and yet; but even so; despite that
Conjunction used to express a contrast or unexpected result, similar to なのに but following the plain copula だ. Often used in spoken or informal written Japanese.
See also: なのに
彼は一生懸命勉強した。だのに、試験に落ちてしまった。
He studied very hard. And yet, he failed the exam.
天気予報は晴れだった。だのに、急に雨が降り出した。
The weather forecast said it would be sunny. But even so, it suddenly started raining.