be on the right/wrong side of 40, 50, etc.
be (on) the right side of (an age)
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!
be (on) the wrong side of (some age)
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!
Farlex Dictionary of Idioms. © 2022 Farlex, Inc, all rights reserved.
be on the ˌright/ˌwrong side of ˈ40, ˈ50, etc.(informal, often humorous) be younger/older than 40, 50, etc: ‘How old is she?’ ‘On the wrong side of forty, I’d say.’
Farlex Partner Idioms Dictionary © Farlex 2017