Fast
Fast adjective - Moving, proceeding, or acting with great speed.
Motionless and fast are semantically related. In some cases you can use "Motionless" instead an adjective "Fast".
Motionless
Motionless adjective - Not in physical motion.
Fast and motionless are semantically related. Sometimes you can use "Fast" instead an adjective "Motionless".
Mutual synonyms
Both words in one sentence
- It's completely motionless as long as someone is looking at it, but it can move inhumanly fast if it's out of sight.
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Herons and similar wading birds have the same type of muscle in their necks, allowing them to perform a lightning-fast lunge attack with their heads while the rest of their body remains motionless to avoid alerting fish to their presence.
Source: Deadly Lunge - Combine this with the fact the Constructors tend to remain motionless once you're in range, and their critical hit location is a glowing red light on their face that doesn't move, Assassins can deconstruct the Constructor so fast that party members can be left wondering what the hell happened.
Cite this Source
Motionless and Fast. (2016). Retrieved 2026, August 15, from https://thesaurus.plus/related/fast/motionless
Fast & Motionless. N.p., 2016. Web. 15 Aug. 2026. <https://thesaurus.plus/related/fast/motionless>.
Motionless or Fast. 2016. Accessed August 15, 2026. https://thesaurus.plus/related/fast/motionless.
Google Ngram Viewer shows how "fast" and "motionless" have occurred on timeline