We all know a person who acts as if he or she knows it all and is dismissive of other people’s opinions, comments or suggestions.
In English, the best word to describe such a person is know all this (or know-it-all) whereas in Italian you may hear people using these terms smart people (for a man) and smart (for a woman).

Here are the definite and indefinite articles for the masculine and feminine forms of the word:
- know-it-all = know-it-all (rice)
- Experts = know-it-all (rice)
- know-it-all = know-it-all (F.)
- smart people = know-it-all (F.)
- omniscient = omniscient (rice)
- Saint’s = (some) omniscient (rice)
- omniscient = omniscient (F.)
- some smart people = (some) omniscient (F.)
If you want to say “become an omniscient” or “act/sound like an omniscient”, you can use this expression be smart (literally a jack-of-all-trades).
I don’t want to be a smart guy, but it seems to me…
I don’t want to sound like an omniscient, but in my opinion…

The word comes from Sensibleexpressed as an adjective Sensible or knowingas a noun means know-it-all…by adding the extended suffix -one and – Then At the end of a noun, you can give the meaning “big” (literally “great knower”).
Some synonyms you may come across are:
- know all this
- know all this (mainly used by young people who think they are more sensible than adults)
- Judge (literally “sentences spitter”, less common but interesting due to the way it’s constructed)