know-it-all

(noun) a person who is annoying because they are intelligent and like to show it

Example Sentences:

A: I think we should go to Jamaica for our vacation.
B: Did you know that the capital of Jamaica is Kingston? And that they are one of the largest…..
A: Please don’t be a know-it-all.

A: What’s the weather supposed to be like tomorrow?
B: Sunny with a 30% chance of rain, turning to 60% in the evening, and the next day will be overcast and cloudy.
A: Know-it-all.

From the Blogs:

Harvard Square: Know-it-all Capital of the Universe

Media:

Similar idioms:

1. smart alec
2. smart aleck
3. smart ass