Lewis & Short

dē-mŏrĭor, mortuus, 3, v. dep. n., to die off, to die, depart, decease (i. e. from an office, out of a circle of associates, etc., cf. Fabri ad Liv. 23, 21, 7. In the class. per. only in the perf. or part. perf.; not found in Caes. and the Aug. poets).

  1. I. Lit.: paene sum fame demortuus, Plaut. Stich. 1, 3, 62: cum esset ex veterum numero quidam senator demortuus, Cic. Verr. 2, 2, 50, § 124; cf.: tantum hominum demortuum esse, ut, etc., Liv. 40, 19; 26, 23; Curt. 8, 10: alii sunt alias, nostrique familiares fere demortui, Cic. Att. 16, 11 fin.: posse evenire, ut demoriantur mancipia, Dig. 4, 4, 11, § 5.
    So in pub. law lang.: in demortui (magistratus) locum creatur, sufficitur, etc., Liv. 5, 31 Drak.; 23, 21 sq.; Cic. Verr. 2, 4, 5, § 9; Suet. Caes. 41 al.
  2. II. Trop.
    1. A. To depart, be gone: potationes plurimae demortuae, Quot adeo cenae, quas deflevi, mortuae! Plaut. Stich. 1, 3, 58: demortua vocabula, obsolete, Gell. 9, 2, 11.
    2. B. With acc. pers., to be dying for love of any one (cf. depereo): ea demoritur te, Plaut. Mil. 4, 1, 23; 4, 2, 49.