Alternative forms 
- phthisick (obsolete)
From Middle English tisike, from Anglo-Norman, from Latin phthisicus (“suffering from tuberculosis”), from Ancient Greek φθισικός (phthisikos, “consumptive”), from φθίσις (phthisis, “tuberculosis, consumption”)
phthisic (plural phthisics)
- (pathology) A wasting illness of the lungs, such as asthma or tuberculosis; phthisis.
- (pathology, formerly) Any wasting disease.
- A person suffering from phthisis.
- Any wasting or shrinking of another body part such as, for example, the eye (phthisis bulbi).
Derived terms 
phthisic (not comparable)