“certain” in Latin

certus (general term both objectively of persons and things whose nature is certain; and subjectively of a person who feels certain, etc.): firmus (firm, resisting any attempt to alter or destroy it; hence unchangeable, of things and persons): stabilis (not yielding or varying, steadfast: of persons and things): constans (steady, consistent: opposed to varius, mobilis): fidus (which may be confidently trusted: of persons, and also of things, as in pax fida). (The words are found in this connection and order), certus et constans; firmus et constans: exploratus (the truth or certainty of which has been ascertained): status (fixed, not subject to alteration; e.g., cursus siderum, Plin.): ratus (calculated; hence settled, immutable; e.g., in onmi aeternitate rati immutabilesque siderum cursus). (The words are found in this connection and order), ratus et certus; constans et ratus; ratus atque firmus; stabilis. fixus, ratus; certus, ratus, firmus, fixus: indubius, non dubius (not indubitatus in good prose): finitus: definitus (defined, marked out accurately; also of notions). (The words are found in this connection and order), certus et definitus. A certain income, reditus status: certain expenses, expensae statae (opposed to sumtus fortuiti): a certain friend, amicus certus, fidus, firmus et stabilis: certain death, mors praesens: death is certain, mors nos omnes manet: a certain remedy, remedium praesens: is this certain? satin hoc certum est? to live in the certain hope, etc., certo sperare; non dubiam spem habere: that he might make certain of this, etc., ut hac de re certior fieret, etc.: without being certain of the fact, sine certa re (Caes., B.G., 5, 29): to know for certain, certo scire, less commonly certe scire [Practical Introduction, ii, , 560-2], also pro corto scire. I know it for certain, certum scio; certo scio; certo comperi; certuin or pro certo habeo: to know anything on certain authority, aliquid certis auctoribus comperisse: to assert anything as certain, pro certo affirmare aliquid: that my letter may be the mere certain to reach you, quo fidelius litterae ad te perferantur: by or against a certain day, ad diem; ad diem dictum, constitutum, praestitutum; in diem certum. ☞ Certain may sometimes be translated by non dusito (or non dubium est) quin. “It is certain that the thing may be done,” non dubito (or non dubium est, or non videtur esse dubium), quin hoc fieri possit.

Indefinitely, quidam (τες; general term of what one purposely does not, or, from want of knowledge, can not, name; often contemptuously, as in homines quidam, etc.): certus (stronger than quidam: of what one has good reasons for not choosing to name: quibusdam de causis, for certain reasons, which the hearer or reader may or may not divine, but which the speaker does not think it necessary to mention: certis de causis, for reasons which the hearer or reader can not know, but which the speaker does not think it advisable to mention): nescio qui or nescio quis (somebody or other, the speaker himself does not exactly know who; according to Gürenz, nescio quis, with something of depreciation).