What is the meaning of OK boomer in genz slang?

The meaing of the word OK boomer in genz slang means the following:

• A pejorative phrase directed at members of the Baby Boomer generation, dismissing their views as outdated.
• Commonly used in generational debates and online discussions.

Example

When my dad started ranting about 'kids these days', I just said, 'OK boomer.'