noun
totally hopeless old guy
Slang abbreviation of まるでダメなおっさん (marude dame na ossan), used to describe a middle-aged man who is seen as completely useless or pathetic. Often used humorously or derogatorily.
あの上司、本当にマダオだよね。
That boss is a total hopeless old guy, isn't he.
マダオと呼ばれないように頑張ろう。
Let's work hard so we don't get called a hopeless old guy.