What is the Latin word for firm?

The usual Latin words for “firm” are firmus, stabilis, cōnstō; also offirmō, solidus, dūrō. The right choice depends on the sense; see the distinctions below.

English → Latin

“firm” in Latin

firmusstrong, powerful; stable, firm; faithful, steadfast, true stabilisfirm, steadfast, steady, sure, stable, stationary (that stands firm); established, enduring, durable, immutable, lasting cōnstōto stand together; to stand still; to remain the same; stand firm; to agree, correspond, fit offirmōto make firm, durable, steadfast; to hold fast to, persevere in; to be obstinate solidusdense, solid, not hollow; whole, entire, thorough, full; firm dūrōto harden, make hard; to last or endure; to dry vacillōto sway to and fro; to stagger, reel, totter; to waver, hesitate corpusbody, person (person when used to mean "human body", e.g., "on one's person"); substance, material (physical, perceptibl terradry land (as opposed to watery parts of the Earth); ground, floor (the surface of the land); earth, soil, dirt, clay, cl

The English word firm itself goes back to Latin firmus, through ferma.

Riddle & Arnold A Copious and Critical English–Latin Lexicon, 1864

firm adj.

firmus (that will resist external impressions, dissolution, destruction, etc.; hence, also, “steadfast;” opposed to labans, vacillans, and, for want of a suitable adjective, to imbecillus): stabilis (that can stand firm, or upon which one may stand firm); (The words are found in this connection and order.) stabilis et firmus; firmus stabilisque: constans (remaining the same, not changeable; like the course of the heavenly bodies, etc. All three, also, tropical for invariable, steadfast): offirmatus (IMPROP.; obstinate, inflexible): solidus (solid, etc.; PROP.; e.g., corpora, terra): duraturus (likely to last; of bodily things only). To stand firm, *immotum stare; or stare only; opposed to cadere or corruere: firm courage, animus firmus: to be firm, stare animo (of one person); stare animis (of several): to remain firm, stare (in) aliqua re (e.g., in one’s opinion, in sententia); da gradu non dejici (not to be confounded, lose one’s presence of mind, etc. Cic.); in anything, perseverare in re; firm and lasting friendship, amicitia firma et perpetua: a firm friend, amicus firmus, stabilis, constans, certus; firmus amicus ac fidelis (Cic.): to use firm language, oratione uti stabili ac non mutata: firm allies, socii fideles (Cic.); socii boni ac fideles, or boni fideles (both Liv.): a firm hand, manus strenua or stabilis (steady; Cels.; ☞ not manus firma). ☞ Terra firma should be terra continens. With a firm unshaken mind, stabili et firmo animo: a firm mind, animus obstinatus: a man of firm principles, homo constans: a firm resolution, consilium certum: to have a firm conviction of anything, de aliqua re sibi persuasisse.

Quick answer

What is the Latin word for firm?: The usual Latin words for “firm” are firmus, stabilis, cōnstō; also offirmō, solidus, dūrō. The right choice depends on the sense; see the distinctions below.

Entry from J. E. Riddle & T. K. Arnold, A Copious and Critical English–Latin Lexicon (rev. C. Anthon, New York: Harper, 1864), digitised by Fergus J. P. Walsh, CC BY-SA 4.0; Latin markup adapted by latindictionary.co.