Flat
Flat adjective - Having a surface without bends, breaks, or irregularities.
Usage example: preferred riding her bike on a flat road
Smooth is a synonym for flat in characteristic topic. In some cases you can use "Smooth" instead the word "Flat" as an adjective or a verb or an adverb, when it comes to topics like even. popular alternative
Smooth
Smooth adjective - Having a surface without bends, breaks, or irregularities.
Usage example: a smooth skating rink
Flat is a synonym for smooth in even topic. You can use "Flat" instead the word "Smooth" as an adjective or a noun or a verb or an adverb, if it concerns topics such as characteristic, property, calm, level. popular alternative
Both words in one sentence
-
By comparison the ocean is quite flat and smooth and makes it pretty easy for a missile to find a target, necessitating a rather different seeker design.
Source: Just Plane Wrong -
Seeker Bears has "flat-faces"/"no-claws"/"smooth-pelts" for humans (depending on the species saying it), "firebeasts" for vehicles, "BlackPath" for roads, and "death sticks" for guns.
Source: Call a Rabbit a "Smeerp" -
They either have the superhuman strength or speed or ability to simply run up a smooth, flat, vertical surface at high speeds, even if logically they shouldn't be able to.
Source: Wall Run
Cite this Source
Smooth and Flat. (2016). Retrieved 2026, August 14, from https://thesaurus.plus/related/flat/smooth
Flat & Smooth. N.p., 2016. Web. 14 Aug. 2026. <https://thesaurus.plus/related/flat/smooth>.
Smooth or Flat. 2016. Accessed August 14, 2026. https://thesaurus.plus/related/flat/smooth.
Google Ngram Viewer shows how "flat" and "smooth" have occurred on timeline