Is Callous an Adverb?

In a callous manner; done without regard to others' sensitivities.

Is callous an adjective or adverb?

We often use callous, as an adjective or a verb, in the metaphorical sense for emotionally hardened. If someone is unmoved by other people's problems, you might say he shows a callous indifference to human suffering or that his heart has been calloused by his own problems.

What is the adverb form of callous?

They callously disregarded the concerns of ordinary people.