IPA: /ˈslɪp.ər.ɪ.nəs/
KK: /ˈslɪpərɪnəs/
The quality or state of being slippery, which means difficult to hold or walk on due to a smooth or wet surface.
The slipperiness of the ice made it hard for the skaters to maintain their balance.
Slipperiness → It is formed from "slippery" (from Old English "slipor", meaning smooth or gliding) and "-ness" (a suffix used to form nouns indicating a state or quality). The word "slipperiness" refers to the quality of being slippery or the state of being smooth and difficult to hold or walk on.
Think of the word 'slippery' which describes something that is smooth and can cause slipping, and remember that 'slipperiness' is the state of being slippery.