CHALLENGING (adjective) definition and synonyms | Macmillan Dictionary.

Is challenge a noun verb or adjective?

verb (used with object), chal·lenged, chal·leng·ing. to summon to a contest of skill, strength, etc. to take exception to; call in question: to challenge the wisdom of a procedure.

Is challenging an adjective or adverb?

it is both a verb and an adjective.