Meaning of the word "mad as a March hare" in English

What does "mad as a March hare" mean in English? Explore the meaning, pronunciation, and specific usage of this word with Lingoland.

mad as a March hare

US /mæd æz ə mɑrtʃ hɛr/
UK /mæd æz ə mɑːtʃ hɛə/

Idiom

completely crazy or insane

Example:
After working for 24 hours straight, he was as mad as a March hare.
Her ideas for the party were so wild, she was mad as a March hare.