Adab (আদব), from the Arabic word Aadaab (آداب), meaning respect and politeness, is a hand gesture used by South Asian Muslims while greeting. It is associated with the culture of south Asian Muslims.
Since the normal greeting of Muslims i.e. "Assalamu 'Alaykum" was meant for Muslims only, and Muslims in India lived in a multi-faith and a multi-lingual society, this alternative form of greeting was coined. Fundamentalist elements in the society oppose the use of "Adab" in an all-Muslim society.
The gesture involves raising the right hand towards the face with palm inwards such that it is in front of the eyes and the finger tips are almost touching the forehead, as the upper torso is bent forward. It is typical for the person to say "adab arz hai", or just "adab". It is often answered with the same or the word "Tasleem" is said as an answer or sometimes it is answered with a facial gesture of acceptance.
In popular culture today, the adab is often associated with the courtly culture of the Muslim Nawabs.