缺陷 (quē xiàn) literally combines 缺 (‘to lack, be missing’) and 陷 (‘to sink, cave in, or fall into’), suggesting something that is fundamentally incomplete, damaged, or imperfect—like a structural gap or functional shortcoming. It refers to an inherent flaw or defect in an object, system, person, or abstract concept (e.g., a design flaw, a genetic abnormality, or a weakness in logic).

The word carries a neutral-to-negative connotation and is commonly used in technical, medical, engineering, and evaluative contexts. Unlike colloquial terms like 毛病 (máo bìng, ‘problem’ or ‘fault’), 缺陷 implies a more objective, often measurable imperfection—such as a manufacturing defect in electronics or a congenital defect in medicine. It appears frequently in formal writing, quality control reports, and clinical diagnoses.