- slippery, slippy - being such as to cause things to slip or slide; "slippery sidewalks"; "a slippery bar of soap"; "the streets are still slippy from the rain"
Antonyms: nonslippery, nonskid, nonslip
- slippery, tricky, teflon - not to be trusted; "how extraordinarily slippery a liar the camera is"- James Agee; "they called Reagan the teflon president because mud never stuck to him"
Antonyms: trustworthy, trusty (indirect, via untrustworthy)