Having or composed of only one thing, element, or part. See Synonyms at pure. Not involved or complicated; easy: a simple task. See Synonyms at easy. Being without additions or modifications; mere: a simple "yes\u201d or "no.\u201d Having little or no ornamentation; not embellished or adorned: a simple dress. Not elaborate, elegant, or luxurious. See Synonyms at plain. Unassuming or unpretentious; not affected. Having or manifesting little sense or intelligence. Uneducated; ignorant. Unworldly or unsophisticated. See Synonyms at naive. Not guileful or deceitful; sincere. Humble or lowly in condition or rank: a simple woodcutter. Ordinary or common: a simple head cold. Being a fundamental or rudimentary element; basic. Not important or significant; trivial. Biology Having no divisions or branches; not compound: a simple leaf; a simple eye or lens. Music Being without figuration or elaboration: a simple tone. A single component of a complex, especially one that is unanalyzable. A fool; a simpleton. A person of humble birth or condition. A medicinal plant or the medicine obtained from it.