Source : Webster's Revised Unabridged Dictionary (1913)

Slippy \Slip"py\, a. [AS. slipeg.]
   Slippery.

Source : WordNet®

slippy
     adj : 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" [syn: {slippery}] [ant: {nonslippery}]
     [also: {slippiest}, {slippier}]