The term "know it all" is often associated with someone who is overly confident in their knowledge and quick to offer unsolicited advice. There are a few synonyms that come to mind when describing such individuals, including "smarty-pants," "wise guy," and "sage." Additionally, "smart aleck," "egotist," and "conceited" are also fitting terms that describe someone who often acts like a know it all. It's important to remember that while knowledge and confidence can be admirable qualities, it's crucial to approach situations with humility and stay open-minded to new perspectives and ideas.