The phrase "smart alec" refers to someone who is overly clever or self-assured in an annoying way. There are several synonyms for this term and some of them include "know-it-all," "wise guy," "wise-cracker," "smarty-pants," "show-off," "prig," and "conceited." These words describe a person who enjoys showing off their intelligence, often to the point of irritating others. While being intelligent is a desirable trait, using it to belittle others is not. Therefore, it's essential to exercise caution while using these words to describe someone so as not to come across as rude or derogatory.