- to live together as spouses without being legally married.
- to have illicit sexual relations.
- to live in a shack: He's shacked up in the mountains.
Origin of shack1
British Dictionary definitions for shack up (1 of 3)
British Dictionary definitions for shack up (2 of 3)
Word Origin for shack
British Dictionary definitions for shack up (3 of 3)
Word Origin and History for shack up
1878, American English and Canadian English, of unknown origin, perhaps from Mexican Spanish jacal, from Nahuatl xacalli "wooden hut." Or perhaps a back-formation from dialectal English shackly "shaky, rickety" (1843), a derivative of shack, a dialectal variant of shake (v.). Another theory derives shack from ramshackle.
Slang meaning "house" attested by 1910. In early radio enthusiast slang, it was the word for a room or office set aside for wireless use, 1919, perhaps from earlier U.S. Navy use (1917). As a verb, 1891 in the U.S. West in reference to men who "hole up" for the winter; from 1927 as "to put up for the night;" phrase shack up "cohabit" first recorded 1935 (in Zora Neale Hurston).
Idioms and Phrases with shack up
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]
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]