IPA: /ˈslɪpəriər/
KK: /ˈslɪpəriər/
More difficult to hold on to or walk on than something that is slippery.
The ice on the road was slipperier than I expected, making it hard to drive safely.
Comparative: slipperier
Superlative: slipperiest
Slipperier → It is formed from "slippery" (from Old English "slypere", meaning smooth or gliding) and the comparative suffix "-er" (meaning more). The word "slipperier" means more slippery or having a greater quality of being smooth and difficult to hold.
Think of something that is 'smooth' ('slippery') and then remember that 'slipperier' means it is 'more smooth' or 'more difficult to hold onto'.
No commonly confused words.