Looking for the word that means, sure of oneself but actually is quite uninformed. Person who gets it is... cool.
can't think of one word by itself off the top of my head, but you could use 'hubristic ignorance' in combination.
Noun 1. delusions of grandeur - a delusion (common in paranoia) that you are much greater and more powerful and influential than you really are delusion, psychotic belief - (psychology) an erroneous belief that is held in the face of evidence to the contrary megalomania - a psychological state characterized by delusions of grandeur