downside I. \ˈ ̷ ̷ˌ ̷ ̷\noun 1.: the under or lower side < a gaily tilted hat with a decorative clasp on the downside > 2.: a trend downward (as of prices) — used chiefly in the phrase on the downside II. noun : an unappealing, disadvantageous, or negative aspect < the downside of fame >