sap·ro·pel·ic \| ̷ ̷ ̷ ̷|pelik\adjective Etymology: International Scientific Vocabulary sapropel + -ic 1.: living in mud or ooze composed chiefly of decaying organic matter (as various freshwater protozoa) 2.: of, relating to, or derived from sapropel < the organic carbon may be humic (coaly) or sapropelic (bituminous) — F.J.Pettijohn >