Synonyms of know-it-all

1 Syllable

brain

2 Syllables

snobby, longhairs, gascon, wiseass, gasbag, bigmouth, hotshot, smarties, snotty, ranters, sniffy, egghead, ranter, strutter, boastful, smarty, galler, vaunter, cockier, bookman, braggart, bighead, windbag, smart-ass, wise-ass, cocky

3 Syllables

blusterer, bull-thrower, cold-shoulder, biggety, jabberer, motor-mouth, conceity, prideful, savantes, saucebox, trumpeters, uppity, arrogant, conceited, wiseacre, smarty-pants, trumpeter

4 Syllables

wisenheimer, self-important, swollen-headed, self-centered, hifalutin, self-applauding, self-confident, intellectual

5 Syllables

self-interested, self-aggrandizing