What is the Latin word for stagnant?

The usual Latin words for “stagnant” are stāgnō, rĕsĕs, lentus; also torpeō, piger, Stātius. The right choice depends on the sense; see the distinctions below.

English → Latin

“stagnant” in Latin

stāgnōto cover the land as a lake; to become a pool; to stagnate rĕsĕsthat remains sitting lentussticky, tenacious; slow, sluggish; flexible, pliant torpeōto be stiff, numb, torpid or motionless; to be stupefied or astounded; to be inactive or listless pigerbackward, slow, dull, lazy, indolent, sluggish, unwilling, motionless, inactive, inert; unwilling, reluctant, averse Stātiusa masculine praenomen, famously held by aquawater

The English word stagnant itself goes back to Latin stāgnum, through stagnans.

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

stagnant

stagnans (post-Augustan): reses (e.g., aqua, Varr., R.R., 3, 17, 8): lentus: torpens († lacus, Statius): piger (sluggish). (The words are found in this connection and order.) stagnans pigerque (e.g., aquae, Plin.).

Quick answer

What is the Latin word for stagnant?: The usual Latin words for “stagnant” are stāgnō, rĕsĕs, lentus; also torpeō, piger, Stātius. 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.