Translation of "Nonsensical" in Japanese

His nonsensical behavior is shocking.

彼の馬鹿げた振る舞いには呆れるよ。

Some crazy people would be driven by nonsensical mantras

最終的には 「おもしろければ なんでもいいんだ」と

- He was so drunk that his explanation did not make sense.
- He was so drunk, his explanations were nonsensical.

酔っていたので、彼の説明は意味不明でした。