Fetching details from the dictionary...

absurd; unreasonable; nonsensical; preposterous; incoherent
extreme; senseless; reckless; wanton
disorderly; chaotic; confused; messy
incredibly; really; so; super
台風で部屋の中が滅茶苦茶になってしまった。
The typhoon made the room a complete mess.
彼の説明は滅茶苦茶で全く分からなかった。
His explanation was a mess and I didn't understand at all.
滅茶苦茶な予定を立てて結局失敗した。
I made a crazy schedule and ended up failing.