Smooth is often a descriptor bourbon drinkers use, but it's not a term to bring up at a bourbon tasting or when you're among connoisseurs of the iconic American spirit.
The term "smooth" is vague and doesn't describe any of the flavors in a good bourbon. Experts will judge you for using the term, as it adds nothing to the discourse.
You can say whether you like the brand you're trying, and it’s okay to keep it simple. You're better off referencing specific flavors and feels in detail.
The flavor wheel is an excellent way to help familiarize yourself with standard wood-aging aromatics like chocolate, honey, vanilla, or caramel.
Smooth is not on the flavor wheel. While it's nice if your bourbon is smooth, maybe just keep this thought to yourself during your next bourbon tasting.