The act of making a challenge.
"The challenging move left the opponent unsure of their next step."
In plain English: A challenging is not actually a word; you probably meant to ask for an adjective, which describes something that requires great effort or skill to do successfully.
"The game presented a challenging moment when we all had to work together to win."
present participle of challenge
"The lawyer challenged the witness to answer the question without hesitation."
In plain English: To challenge something means to question it or argue against what someone says.
"The difficult puzzle challenged me to think more creatively than usual."
requiring full use of your abilities or resources
"ambitious schedule"
"performed the most challenging task without a mistake"
stimulating interest or thought
"a challenging hypothesis"
"a thought-provoking book"
Difficult, hard to do.
"The new climbing route is extremely challenging because of its steep walls and lack of handholds."
The word challenging comes from Middle English chalengynge, which was formed by adding the suffix -ing to the verb challenge. It originally referred to the act of issuing a formal demand or contest, and its meaning has remained consistent as it traveled into modern usage.