Is concerned a verb or an adjective?

"Concerned" can be both a verb and an adjective, depending on its context. Here's how:

Verb:

* Past participle: "He was concerned about the safety of his family."

* Past tense: "She concerned herself with the details of the project."

Adjective:

* Describing a state of worry: "He had a concerned look on his face."

* Describing someone who cares about something: "The concerned citizen contacted the authorities."

So, to determine whether "concerned" is a verb or an adjective, you need to look at how it's used in a sentence.