Two little used and great descriptive words:

phthisis (pronounced alternately: ti’sis, te’sis, thi’sis, and the’sis; from Greek: phth- a wasting) obsolete medical term for consumption, most typically tuberculosis. A wasted (consumed) person is ‘phthisic’

Note: I prefer the ‘thi’ sounding pronunciation for the noun, but the hard ‘t’ for the adjective (my own strangeness). Also, I have seen it spelled with a ‘y’ instead of the ‘i’, but both Dorland’s and Stedman’s medical dictionaries list it with the ‘i’. I have also (old medical journals/articles) seen the adjective spelled ‘phthitic’ and ‘phthytic’.

Another favorite of mine:

wizened (wiz’ end; Old English wisnian – to dry up) to dry up, wither, or shrivel

Thus a very sickly person can be described (I love documenting this in the charts and few people have any idea what I am saying…) as: “phthisic and wizened” – so much more colorful than “wasted and dehydrated”!!

Same root/meaning as ‘phthisis’ leads to two other lovely words:

phthisiophobic – intense, morbid fear of tuberculosis

phthisiotherapeutic – of or related to the treatment of tuberculosis