know every trick in the book
To be aware of or knowledgeable in every possible way to do or achieve something, especially ways that are clever, cunning, or ethically questionable. My dad was a shrewd businessman who knew every trick in the book to seal a deal. If you want girls to be interested in you, my older brother knows every trick in the book.
know full well
To know or be aware of something without any possible doubt. You know full well why I'm upset with you, so there's no use playing dumb! We know full well that many families are struggling to make ends meet, but these tax increases are unavoidable.
know (someone) in the biblical sense
To have (or have had) sexual intercourse with someone. In certain versions of the Bible, "to know someone" means to have sexual relations with him or her, as in Genesis 4:1: "And Adam knew Eve his wife, and she conceived and bore Cain." Bob: "You know Samantha quite well, right?" Dave: "Well, I don't know her in the biblical sense, if that's what you're asking." John is looking very well these days. I'd like to get to know him in the biblical sense, if you know what I mean.
(the) next thing (one) knows
All of a sudden; out of nowhere; without warning. I was standing in line, minding my own business, when the next thing I know, a gunman runs into the bank and starts screaming at us to get on the ground! Tammy had only been on a few dates with Mark, but this one had been going smoothly. Next thing she knew, he got on one knee and proposed to her.
know a hawk from a handsaw
To be able to tell two things apart. The phrase comes from Shakespeare's Hamlet. Of course I know which twin is which, I know a hawk from a handsaw, after all!
know chalk from cheese
To be able to tell two things apart (especially by recognizing their differences). Of course I know which twin is which, I know chalk from cheese, after all! Leah has a beauty mark under her left eye, and Deena doesn't.
know for a fact
To have definitive knowledge of something. I know for a fact that he cheats in cards! I saw the ace up his sleeve. My mom says she knows for a fact that I'm getting the internship at her company, but I won't believe it until the recruiter calls me.
know (something) inside and out
To be well-versed in and/or very familiar with something. I'm ready for this exam—I know genetics inside and out! I think Mary will do great at the audition, now that she knows the dance inside and out. These cabbies know the city streets inside and out.
know (one's) beans
To be knowledgable about and/or very familiar with something. I had no idea you were such a good piano player—you really know your beans!
know (someone)
To have a familiarity with someone; to know who someone is. Such familiarity can range from close friendship to having only met someone once. Oh yeah, I know Mr. Meyers, he used to be my neighbor. He knew Vanessa long before she became a famous singer.
know what's o'clock
To be attentive and aware of all that is going on. Those students thought they could get away with cheating in my class, huh? Too bad I know what's o'clock!
know which way the wind blows
To be able to anticipate how a certain course or situation is likely to develop. These politicians know which way the wind blows regarding public opinion on the issue, and you can bet they'll vote accordingly.