Kife means: Slang for to steal - to take something that doesn't belong to you. A relatively obscure term in this sense, appearing in various regional slang dictionaries without a clear regional home. The word. It is informal slang, fine in casual speech but not suited to formal contexts. It has drug-related associations; worth a calm conversation about which side of the topic your teen is on. As a place or proper-name reference it is purely descriptive.