Know-it-all
WordNet
noun
(1) Someone who thinks he knows everything and refuses to accept advice or information from others
WiktionaryText
Noun
- Someone who acts as if he/she knows everything and believes him/herself above others as a result, normally intended as a pejorative.
- I had it figured out, but this know-it-all marched in with a better idea.
See also
- polymath
- smarty pants
- smart aleck
- wise guy
- clever dick
- wisenheimer
- smarty
- wisecracker