phthisis, phthisic 1. A disease characterized by the wasting away or atrophy of the body or a part of the body. 2. A wasting disease; especially, pulmonary tuberculosis of the lungs. The term was formerly applied to many wasting diseases, but is now usually restricted to pulmonary phthisis, or consumption. Found on http://www.wordinfo.info/words/index/info/view_unit/1653/2