Unexpected; contrary to expectations — something that comes as a surprise or by chance.
思いがけない知らせが届いて、今日は仕事どころではなかった。
An unexpected message arrived, and I couldn't focus on work today.
思いがけない出会いで大学時代の友人と再会した。
I ran into a college friend by chance and we met again unexpectedly.
彼女の思いがけない頼みを断るのは難しかった。
It was hard to refuse her unexpected request.