The Thai greeting referred to as the wai (Thai: ไหว้) or in Lao as kub consists of a slight bow, with the palms pressed together in a prayer-like fashion. It is very similar to the Indian namasté and the Cambodian sampeah. The higher the hands are held in relation to the face and the lower the bow, the more respect or reverence the giver of the wai is showing.

The wai is also common as a way to thank someone or apologise.

The word often spoken with the wai as a greeting or farewell is sawatdee (สวัสดี). Phonetically, the word is pronounced "sa-wat-dee". This word was coined in the mid-1930s by Phraya Upakit Silapasan of Chulalongkorn University. This word, derived from the Sanskrit svasti (meaning "well-being"), had previously been used in Thai only as a formulaic opening to inscriptions. The strongly nationalist government of Plaek Pibulsonggram in the early 1940s promoted the use of the word sawatdee amongst the government bureaucracy as well as the wider populace as part of a wider set of cultural edicts to modernise Thailand.

Origin

The wai originated from an ancient greeting that was done to show neither individual had any weapons. There exist multiple versions of the greeting based on social class, gender, and age.

One speculation is that it comes from Buddhism. After certain prayers, one must clasp their hands together and bring it down towards the ground three times.