What does someone mean when they say “flip him the bird”?
The phrase refers to pointing a middle finger at someone in order to swear at them. This colloquial form of profanity was popularized by Robin Williams in the movie Good Morning Vietnam.
Instruction: What does someone mean when they say “flip him the bird”?
Context: 
Response: The phrase refers to pointing a middle finger at someone in order to swear at them. This colloquial form of profanity was popularized by Robin Williams in the movie Good Morning Vietnam.