know-it-all

• POS: Adjective, Noun, Noun Phrase

CIDE DICTIONARY

know-it-all, n. 

 One who knows everything;
"the use of this term implies that the speaker disapproves of this behavior, and may think that it is unjustified"  [1913 Webster]

THESAURUS

know-it-all

Narcissus, aggressively self-confident, biggety, braggart, bumptious, chesty, cocky, conceited, egocentric, egoist, egotist, immodest, individualist, narcissist, narcist, no modest violet, obtrusive, overwise, peacockish, peacocky, perk, perky, pert, puffed up, self-conceited, self-opinionated, smart aleck, smart-alecky, smarty, smarty-pants, stuck-up, swelled-headed, swellhead, wise guy, wiseacre, wisecracker, wisehead, wisenheimer

ROGET THESAURUS

know-it-all

Sage

N sage, wise man, genius, master mind, master spirit of the age, longhead, thinker, intellectual, longhair, authority, oracle, luminary, shining light, esprit fort, magnus Apollo, Solon, Solomon, Nestor, Magi, second Daniel, man of learning, expert, wizard, wiseacre, bigwig, know-it-all, poor man's Einstein, venerable, reverenced, emeritus, barba tenus sapientes.