'Madao' is a word with a series of meanings, based from the manga 'Gintama'. The word bears many different meanings, but they are basically shortened Japanese phrases.
Even though this is not an actual name, in the anime, Taizou Hasegawa, a formally employed government worker would be referred as one, and many of the main characters would refer to Hasegawa as "Madao", though it is unknown which of the many meanings of madao Hasegawa is referred as. Kagura and Shinpatchi are the characters that would address Hasegawa as Madao, though there are some instances that they wouldn't.
1.(ma)ru de (da)me na (o)ssan: good-for-nothing old man
2.(ma)jide (da)ssai (o)yaji: the really uncool old man
3.(ma)ssa ni (da)rusou na (o)yaji: really uncool-looking old man
4.(ma)ttaku (da)rakushite (o)ssan: really depraved old man
5.(ma)zui (da)shi to (o)age: horrid bean curd
6.(ma)ttaku (da)ijobu ja nai (o)kyaku: customer who's really not all right
7.(ma)tomo ni (da)karetakunai (o)toko: men no one wants to date
8.(ma)ji de (da)kaetai (o)toko: man one seriously wants to date
9.(ma)ttaku (da)masenai (o)toboke: fool who unconvincingly feigns ignorance
10.(ma)ssugu ikite no (da)inashi na jinsei na (o)jisan:
old man who lives as he wants, but accomplishes nothing
1. 'Get out, madao!'
2. 'Check out that madao, trying to act so cool.'
3. 'What a madao.'
4. 'I pity that madao.'
5. 'We should throw this madao out.'
6. 'Call security, we have a madao here.'
7. 'That Madao's so old-fashioned.'
8. 'I'm not hooking any madao up!'
9. 'I'm not convinced, madao.'
10. 'That madao is never going to get anywhere in his life.'