If you say that someone has shacked upwith someone else or that two people have shacked up together, you disapprove of the fact that they have started living together as lovers.
[informal, disapproval]
...the deserters who had shacked up with local women. [VERBPARTICLE + with]
The Government was keen for people to get married rather than shack up. [VERBPARTICLE]
It turned out she was shacked up with a lawyer in New York. [beVERB-ed PARTICLE]
See full dictionary entry for shack
shack up in British English
verb
(intr, adverb; usually foll bywith) slang
to live or take up residence, esp with a mistress or lover
shack up in American English
1. Slang
to live or room (in a certain place)
2.
to live (with one's mistress or paramour)
See full dictionary entry for shack
Examples of 'shack up' in a sentence
shack up
With no cash for food let alone a place to live, they're forced to shack up in a squat.
The Sun (2011)
Chinese translation of 'shack up'
shack up
(inf)
vi
to shack up (with sb)(与(與)某人)同居 ((yǔ mǒurén) tóngjū)