Meaning

adjective severely simple

adjective of a stern or strict bearing or demeanor; forbidding in aspect

adjective practicing great self-denial; - William James

originFrom Ancient Greek αὐστηρός (austērós, “bitter, harsh, astringent”), having the specific meaning “making the tongue dry” (originally used of fruits, wines), related to αὔω (aúō, “to singe”), αὖος (aûos, “dry”).

Etymology from Wiktionary, CC BY-SA 3.0