Let me show you some of the slang words in Hindi that you may hear from some section of the society in India. These are not the taboo words, they are used by the illiterate masses and lower section of the society. These words are also sporadically used in Hindi films and literature, but rarely used in media.
Launda (लौंडा) is used for Boy (लड़का – Ladka).
Chora (छोरा) – Another word which is used quite often for a boy.
Laundiya (लौंडिया) is used for Girl (लड़की – Ladki).
Chori (छोरी) – Another word which is also used quite often for a girl.
Baba (बाबा) – Many people use this word for their father, grandfather or a very old person (male). Hindi word for grandfather is दादा (Dada).
Chacha (चाचा) – Some people also use Chacha for their father though Chacha means uncle.
Dadi Amma (दादी अम्मा) is used for Grandmother (दादी – Dadi). Here, an additional word is used with Dadi (Grandmother). This word is mostly used to tell someone that they are trying to show their superiority.
तू बड़ी दादी अम्मा हो रही है। – Tu (you informal) Badi Dadi Amma ho rahi hai – You are being the smart one.