Up yours!
Definition 1 of 1
Pro Tip 1/3Very Rude
It's highly offensive and can escalate conflicts or insult someone deeply. 
He was so annoying, I just turned around and said, 'Up yours!'
Pro Tip 2/3Not for Polite Company
Avoid using 'up yours!' in professional, educational, or formal social settings. 
No matter how mad you are at your boss, never say 'Up yours!'
Pro Tip 3/3Culturally Sensitive
In some cultures, saying 'up yours!' could be much more provocative than in others. 
Remember, telling someone 'Up yours!' in a foreign country can be really shocking.