›used after a number like 20, 30, etc. to refer to the age of a person who is between 20 and 29, 30 and 39 yearsold, etc., or to a person who is of this age: I'd guess she's thirty-something.Most of these places are aimed at twenty-somethings.
According to sociologists (=people who study the relationships between people living in groups), we are good at lying. As a species, we have developed a remarkable ability to deceive each other (= persuade each other that something false is true). Being able to say things that are not true can help with