It can be a verb or a noun.
As a verb: "I challenge you to show evidence to back up your assertion."
As a noun: "Finding a job in today's economy is certainly a challenge."
adverb
It is an adjective
what part of speech is beneath
i want to know what part of speech is camping
The part of speech is a adjective
The word "aplomb" is a noun. It refers to self-confidence or assurance, especially in a challenging situation.
You think that the most challenging part of this unit will be?
Hardships is a noun, the plural form of hardship.
The part of speech for this particular word is a noun.
part of speech
The part of speech for "answer" is a noun.
what part of speech is beneath
adverb
The part of speech for "explicit" is an adjective.
The part of speech for "lecturer" is a noun.
The part of speech for "rapid" is an adjective.
The part of speech of "came" is a verb.