What is the abstract noun for slippery?

Answer 1

The abstract noun form of the adjective slippery is slipperiness.

• The noun 'slipperiness' is an abstract noun as a word for a quality of evasiveness, unreliability, unpredictability; a word for a concept.
  
• The noun 'slipperiness' is a concrete noun as a word for a physical quality of smoothness, slickness, greasiness, oiliness, iciness, etc.

Note that in making this noun form, the final y in slippery becomes an i. This is a very common pattern for adjectives that end in y and their corresponding noun forms, such as pretty/prettiness and heavy/heaviness.

Answer 2

The abstract noun for "slippery" is slipperiness.