Lewis & Short

sincērĭtas, ātis, f. [sincerus], cleanness, purity, soundness, wholeness (not anteAug.).

  1. I. Lit.: pura (olei), Plin. 15, 6, 6, § 22: firma capitis, Pall. 1, 3: corporis, Val. Max. 2, 6, 8: alia convertenda, quae sinceritatem habent, Col. 4, 26.
  2. II. Trop.: nec summum bonum habebit sinceritatem suam, si, etc., Sen. Vit. Beat. 15: summa vitae, moral purity, Val. Max. 5, 3, 2 ext.: ad perniciem solet agi sinceritas, uprightness, honesty, integrity, sincerity (with recte loqui), Phaedr. 4, 13, 3; so (with probitas) Gell. 14, 2, 5: verborum (with veritas), id. 2, 23, 21.
    1. B. Esp.: sinceritas tua, a form of complimentary address to certain inferior dignitaries, Cod. Just. 7, 62, 26; Cod. Theod. 2, 1, 8; 10, 15, 4; 7, 1, 9.