Smt
Smt has 2 meanings
Shin Megami Tensei
Gamers may use SMT as an acronym for Shin Megami Tensei. Typically, gamers use SMT to refer to the entire series of Shin Megami Tensei games. In some cases, however, gamers may use SMT to refer specifically to the first game in the series (named, as you might've guessed, Shin Megami Tensei).
Publisher Atlus released the first SMT game for the Super Famicom (the Japanese version of the SNES) in 1992. The wild RPG series, which incorporates science fiction, religion, and philosophy, has since become popular both in Japan and overseas. It has also spawned several spin-offs, including the Persona series.
Example
Is it worth going back and playing SMT I?
Personally I wouldn't
Can you score under par in this golf terms quiz?
Smt is a common abbreviation for "something." As such, you might encounter smt in text, chat, forum, or social media messages, when someone has smt on their mind.
Most often, people use smt because they can't be bothered to type out all of something. (Nine whole letters? In this economy?) In some cases, people may instead use smt to circumvent character limits.