The word 'stench' originates from the Old English 'stenċ', which broadly meant 'smell' or 'odor' and was not inherently negative. This Old English term is derived from the Proto-Germanic 'stankwiz', a noun related to the strong verb 'stinkwaną', meaning 'to smell'. The semantic journey from a neutral 'smell' to its exclusively foul modern meaning is a classic example of pejoration, where a word's connotation worsens over time. This shift was likely complete by the Middle English period, solidifying the word's association with powerful, offensive odors.

This is a simplex word of Old English origin. The modern form 'stench' evolved directly from the Old English noun 'stenċ', meaning 'smell, odor, fragrance'. Its functional role is as a complete lexical root.