Best way to explain Agile to a non-PM

Michael -

I'd look at an elevator pitch like "Agile is an adaptive approach through which a team of empowered, engaged generalizing specialists deliver business value early and regularly through close collaboration with customers and other key stakeholders."

Then you can go into details...

Kiron

Agile is a set of practices and a change of mindset within an organization. In general, I convey as value-based [releasable] delivery through short, manageable increments with increased direct stakeholder involvement and frequent demonstrations to provide feedback and pivot if need be.

Obviously, that is very high-level. I tend to focus on the value, inclusion, and frequent delivery aspect.

A good first list might be:

1. Less planning upfront as the level of uncertainty is high
2. Easy to adapt to change unlike traditional projects
3. Involves stakeholders along the way, not just toward the end
4. Deliver features sooner or incrementally
5. Feedback and lesson learned start from the beginning

My other colleagues can add to this.

I would show them the Agile Manifesto in its original form as written in 2001. This is always the starting point for anyone new to Agile. And then everything else flows from here - books, videos, blogs, certifications, methodologies.
https://www.agilealliance.org/agile101/the-agile-manifesto/

You may quote Figure 2-3 from PMI's Agile Practice Guide:
"Agile is a mindset defined by (4) values, guided by (12) principles, and manifested through many different practices. Agile practitioners select practices based on their needs."

As PMI member, you can download PDF of the Agile Practice Guide here:
https://www.pmi.org/pmbok-guide-standards/practice-guides/agile

My colleagues have given very spot on brief on what Agile concept is.
I would a few advantages too while explaining:
1. Adapt to change and respond faster.
2. Detect and fix issues and defects faster.
3. High product quality.
4. Higher customer satisfaction.
5. Early ROI etc

Sorry Sante, but the worst thing you can do is explaining Agile with this list.