challenging vs ambitious

challenging and ambitious both are adjectives.

Word	Noun	Adjective	Verb	Adverb
challenging	No	Yes	No	No
ambitious	No	Yes	No	No

As adjectives, challenging and ambitious are synonyms defined as:

challenging and ambitious: requiring full use of your abilities or resources

challenging (adjective)	ambitious (adjective)
requiring full use of your abilities or resources	having a strong desire for success or achievement
disturbingly provocative	requiring full use of your abilities or resources
stimulating interest or thought