1often ill; in poor health:she was a thin, sickly child
(of a person’s complexion or expression) indicative of poor health:his usual sickly pallor
literary (of a place or climate) causing or characterized by unhealthiness:a sickly vaporous swamp
2(of a flavour, smell, colour, etc.) unpleasant in a way that induces discomfort or nausea:the walls were painted a sickly greenshe liked her coffee sweet and sickly
excessively sentimental or mawkish:a sickly fable of delicate young lovers