It is easier to clearly reevaluate past actions or decisions than when they are being made or done; things are clearer or more obvious when they are reflected upon. A reference to the visual acuity of normal eyesight (20/20 vision). I can see now that having my brother as my legal counsel was unwise, but I guess hindsight is always 20/20. A: "I can't believe I was ever interested in such a self-absorbed jerk." B: "Don't blame yourself. Hindsight is 20/20, after all."

To talk (to someone) very rapidly, hurriedly, and/or energetically. My aunt can get talking twenty to the dozen if you get her on a topic she's passionate about.

A very brief nap or a short sleep. When you have a baby for the first time, you are suddenly forced to learn how to operate on only twenty winks at a time. I'm going to go grab a quick twenty winks before everyone starts arriving for the dinner party.

To be older than a certain age. Why is she dressing like a teenager when she is clearly the wrong side of 40? I'm sore after every workout these days, so I'm definitely on the wrong side of 30!

To be younger than a certain age. You can get away with dressing like a teenager when you're still on the right side of 30. I was never sore after working out when I was on the right side of 40!

Just a little bit younger than a landmark age, such as 20, 30, 40, etc. The thriller centers on a young journalist on the sunny side of 30 discovering the treacherous world of politics in Washington, D.C. What would you know about a business like this? You're still on the sunny side of 20!

A term referring to the use of marijuana. It can also refer specifically to such use on the date April 20 (4/20) or the time 4:20. The origin of the term is debated. Whoa, look at all that smoke—there's some 420 action going on in here! Anybody got some weed so we can celebrate 4/20 the right way?

The ability to determine how some mistake or failure in the past could have been avoided. Often used ironically or sarcastically; sometimes stylized as "20/20 hindsight." I can see now that having my brother as my legal counsel was unwise, but I guess twenty-twenty hindsight isn't much use right now. A: "I can't believe I was ever interested in such a self-absorbed jerk." B: "Don't beat yourself about it. We all have 20/20 hindsight."

Knowledge of what one should have done, because it is easier to clearly reevaluate past actions or decisions than when they are being made or done. A reference to the visual acuity of normal eyesight (20/20 vision). With 20/20 hindsight, I can see now that having my brother as my legal counsel was unwise. A: "I can't believe I was ever interested in such a self-absorbed jerk." B: "Don't blame yourself. We all have 20/20 hindsight."