Depending on whether you are looking for information on the classic survival city-builder game or the literal definition of the word, here are a few "posts" covering different angles:
If you are referring to the antagonists from Halo Wars 2 and Halo Infinite : banished
: Unlike the sleek, purple Covenant, the Banished use a rugged, industrial aesthetic with heavy red armor plating and scrap-metal designs. The Word: "Banished" (Definition) In a literal or legal sense: Depending on whether you are looking for information