1) Weak 
• (a.) Of or pertaining to phthisis; affected with phthisis; wasting; consumptive.
Phthis'ic·al adjective [ Latin phthisicus , Greek ...: confer French phthisique . See Phthisis .] Of or pertaining to phthisis; affected with phthisis; wasting; consumptive. 
phthisical, phthisicky Pertaining to, of the nature of, or affected by phthisis (disease characterized by the wasting away or atrophy of the body or a part of the body).