Is robust a verb or noun?

"Robust" is primarily an adjective. It describes something that is strong, healthy, or vigorous.

However, it can be used as a verb in some contexts, meaning:

* To make something stronger or more resilient: "We need to robust our defenses against cyberattacks."

* To increase the strength or resilience of something: "The new software robustly improves the system's performance."

While "robust" as a verb is less common, it is becoming more widely used in technical and business contexts.