Lewis & Short

immōbĭlĭtas (inm-), ātis, f. [immobilis], immovableness (post-class.).

  1. I. Lit.: aquae (maris mortui), Just. 36, 3.
    Absol., Tert. adv. Hermog. 36 fin.; Cael. Aur. Acut. 2, 37, 195.
    Plur., Arn. 1, 26.
  2. II. Trop., unfeelingness, want of feeling: animi, Lact. 6, 17, 23.