What it means
To give someone the cold shoulder means to deliberately ignore them or act distant so they know they're not welcome. It's that icy little social punishment where someone's being off with you, keeping replies short, dodging eye contact, or pretending you barely exist.
Usage examples
"Ever since I nicked his last biscuit, Dave’s been giving me the cold shoulder at the pub, acting like I’m invisible. Proper childish, mate."
"Ever since the argument she has been giving me the cold shoulder, will not even look my way at lunch."
"Do not give the new guy the cold shoulder just because he is a bit shy, invite him over for a coffee."
"I said one wrong thing in the group chat and now Jess is giving me the cold shoulder like I've committed a federal crime."
"Don't give him the cold shoulder all night, just tell him you're still annoyed and keep it moving."
Where it comes from
This one goes back to early 19th century Scots. A form of it appears as cauld shouther in Sir Walter Scott's The Antiquary from 1816. The core image is simple and sticky: instead of warmth or welcome, somebody turns chilly on you and lets that frost do the talking.