shack up

British  

verb

1. slang  to live or take up residence, esp with a mistress or lover

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shack up Idioms  

1. Sleep together or live in sexual intimacy without being married. For example, They had been dating for two months and then decided to shack up . [ Slang ; first half of 1900s]

2. Stay or reside with, as in I'm shacking up with my cousin till I find a place of my own . [ Slang ; first half of 1900s]

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Example Sentences

Ten contestants are shacked up in an Italian villa and, as the title suggests, they're introduced with a kiss.

From BBC

Distraught and at a loss, Yamazaki shacked up at City Lights’ Grant Avenue office for a few months, his sleeping bag on the floor.

From Los Angeles Times

In the summer of 1921, long before garages became the settings of folkloric Silicon Valley origin stories, Picasso shacked up in one in Fontainebleau, southeast of Paris, to take on his own creative pursuits.

From New York Times

This takes a bizarrely conventional turn in his courtship of Elsa, whom he doesn’t merely shack up with but marries.

From New York Times

But I’m so angry he’s turned into such a walking midlife crisis who left his family to shack up with a morally questionable woman for what I’m sure is sex.

From Washington Post