at it

at it idiom
Vigorously pursuing an activity, especially a fight, but also sex or some other activity. For example, Whenever they play bridge they really go at it (fight), or The new job keeps Tom at it day and night (works hard), or In the spring the dogs are always at it (sex). Shakespeare used this seemingly modern idiom for “fighting” in Troilus and Cressida (5:3): “They are at it, hark!” [Late 1500s]

The American Heritage® Dictionary of Idioms by Christine Ammer. Copyright © 2003, 1997 by The Christine Ammer 1992 Trust. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

Comments
Improve this definition.
Do you have more to add? Share your linguistic knowledge or observation.
/Register to save your comments.