one-sided \ˈ ̷ ̷| ̷ ̷ ̷ ̷\adjective 1. a.: having or existing or occurring on one side only : having one side prominent or more developed < a one-sided leaf > b.: limited to one side : partial, unjust, unfair < a one-sided interpretation > 2.: unilateral < a one-sided decision > • one-sid·ed·lyadverb • one-sid·ed·nessnoun-es