Word parts weak + -ness Pronunciation IPA (key): /ˈwiːk.nəs/ Audio (US)(file) Noun Singular weakness Plural weaknesses Weakness is the condition of being weak. She had become very ill, and her weakness kept her from going to the party. A weakness is a fault. I love the taste of sugar. That's my weakness.Wikiwand - on Seamless Wikipedia browsing. On steroids.Remove ads