absurd; nonsensical; preposterous
荒唐無稽な話だと一笑に付された。
It was dismissed with a laugh as an absurd story.
荒唐無稽に見えた理論が後に証明された。
A theory that seemed preposterous was later proven.
彼の主張は荒唐無稽で誰も信じなかった。
His claims were so absurd that no one believed them.