barmybarm‧y /ˈbɑːmi $ ˈbɑːrmi/ adjective British English informal 
Word Origin
That’s a barmy idea.
Word OriginWORD ORIGINbarmy
ExamplesOrigin:
1400-1500 barm ‘froth that forms on beer when it is being made’EXAMPLES FROM THE CORPUS
Thesaurus- A small pastry hat manifested itself low on my brow, giving the missing barmy look to my regalia.
- However, his appearance in the witness box in support of Gary Blissett in the John Uzzell case was plain barmy.
- I was fourteen then, I'd seen her in National Velvet, and had been barmy about her ever since.
- She's barmy as a bedbug.
- She obviously thought he was barmy.
Longman Language Activatorpeople► crazy
slightly crazy: someone who is crazy does things that are extremely strange or stupid: · My dad told me I was crazy to leave my job.· You agreed to marry him? Are you crazy?· crazy drivers who cause accidents· His friends thought he was crazy when he told them he was going to spend his entire vacation exploring a cave.completely/totally crazy: · Put that gun down! Are you totally crazy?crazy to do something: · You're crazy to lend him all that money - you'll never get it back.
► be nuts also be crackers British spoken informal to be crazy: · People will think you're crackers if you go around talking to yourself like that.· The guy's completely nuts! He goes around in nothing but a pair of shorts in the middle of winter.
► mad/barmy British spoken crazy: · You spent $190 on a pair of shoes? You must be mad!completely mad/barmy: · Monica's new boyfriend is completely barmy. He calls her almost every day from Australia.mad/barmy to do something: · She's mad to turn down an offer like that.· I must have been mad to let myself become involved with someone like Dennis.
► be insane/be out of your mind especially spoken you say someone is insane or out of their mind if they do something or intend to do something that is completely crazy: · Anyone who would take a boat out in this weather must be insane.· Tell the police? Are you out of your mind?
► need your head examined/have taken leave of your senses say this when you think someone is crazy because they have done something that you do not approve of or agree with: · A man who would give his fourteen-year-old son a motorcycle has obviously taken leave of his senses.· If you ask me, anyone who believes in UFOs needs their head examined.
► nutty informal also dotty/batty British informal crazy - use this to describe someone, especially an old person, who behaves in a slightly strange but often amusing way: · Grandma can act kind of nutty at times.· My uncle frequently wore shoes which didn't match, and everyone thought he was a bit dotty.· Next door to us lived a batty old lady who used to have long conversations with her plants.
► be out to lunch/be out of your tree informal someone who is out to lunch or out of their tree behaves in a strange, confused way and does not seem to know what is happening around them: · Our English teacher's really out to lunch -- the class started five weeks ago and she hasn't even asked our names yet.· He is quoted as saying privately that he thinks the former prime minister is 'out of her tree'.
► flaky especially American, informal someone who seems unable to think clearly or do what they should do, and behaves in a strange but often amusing way: · Christy was kind of flaky, but everyone liked her.· You couldn't trust Sam to do anything important. He was too flaky.
► be one sandwich short of a picnic also be a couple of cans short of a six-pack/be a few clowns short of a circus etc strange and slightly crazy: · I always thought Toby was one sandwich short of a picnic. Do you remember how he would sometimes work naked in the garden? · Come on. Let's face it - nobody trusts the guy because he's at least one clown short of a circus.
► have a screw loose informal slightly crazy, often in an amusing way: · "Fernando can be really weird sometimes." "Yeah, he's got a screw loose, no question."
That’s a barmy idea.