Thing you use to look up words you don't understand with definitions filled with words you don't understand and need to look up to understand the definition of the first word you didn't understand.
Man:Look up wishy-washy for me in the dictionary Woman:*looks up wishy-washy in the dictionary*
Dictionary reads: Wishy-Washy: Ineffectual
Ineffectual: Futile
Futile: Futilis that pours out easily, useless
Gullible Person 1: Did you know that 'gullible' isn't in the dictionary?
Gullible Person 2: Really? (Checks dictionary)
Gullible Person 2: Wow! It really isn't in the dictionary!
Gullible Person 1: Oh my God! Give me a look!
A large book containing only "real" words, their "correct" spellings and their (far-less-entertaining-than-urban-dictionary) definitions.
Bill: Gullible.
Josh: what?
Bill: Look in the dictionary, moron.
Josh *flipping through pages* Its not here.
Bill: What?
Josh: Gullible isn't in the dictionary.
Bill: You're shittin' me!
Josh: Nope.