An Etymological Dictionary of Astronomy and Astrophysics

1. Feeble or weak in body or health, especially because of age.
   

2. To unvalidate.

Etymology (EN): M.E. infirm, from L. infirmus “weak, frail, not strong or firm” from → in- “not, opposite of” + firmus, → firm.

Etymology (PE): Nâdeš, from nâ- “not,” → in-, + deš, → firm.