IPA: /ˈsloʊnəs/
KK: /ˈsloʊnəs/
The quality or state of moving or happening at a low speed or taking a long time to do something.
The slowness of the internet made it difficult to stream videos.
Slowness is formed from "slow" (from Old English "slāw", meaning not quick) and "-ness" (a suffix meaning the state or quality of). The word "slowness" refers to the state of being slow or lacking speed.
Think of the word 'slow' to remember that 'slowness' means the quality of not being quick.