Lifshak (emphasis on the second "a") is a tricky trick that allows you to adapt to various kinds of restrictions or solve a certain domestic problem.
The English word LifeHack in literal translation means "hacking life". Here there is an allegory with the Internet, where, by hacking someone's server, you can significantly improve the quality of your own life.
An example of lifhak: if you went on a hike, and you need to make a wash basin, take a plastic bottle, cut off the bottom of it and nail it to the board, turning it upside down. Adjust the water supply by twisting the lid :)
Lifshack is in the list: Slang