The most ignorant, unrealistic, retarded person you have ever met. This person believes they are always right and know, literally, everything about everything. When they have their mind set on something (right or wrong..... usually wrong) you couldn't change it if their life was in jeopardy and having the correct information would save them.

Noun, plural "Kipers" k-eye-purr

Related forms:

verb "to kipe", "kiping"