What part of speech is soundly?

"Soundly" can be two different parts of speech, depending on how it's used in a sentence:

* Adverb: When it modifies a verb, adjective, or another adverb. It describes how something is done or how something is.

* Example: "The baby slept soundly all night."

* Adjective: When it describes a noun, usually in a figurative sense.

* Example: "The argument was soundly defeated." (meaning it was thoroughly defeated)

To determine which part of speech "soundly" is, look at how it's used in the sentence.