Adjective challenging has 3 senses
  1. ambitious, challenging - requiring full use of your abilities or resources; "ambitious schedule"; "performed the most challenging task without a mistake"
    Antonym: easy (indirect, via difficult)
  2. challenging, thought-provoking - stimulating interest or thought; "a challenging hypothesis"; "a thought-provoking book"
    Antonyms: unstimulating, unexciting (indirect, via stimulating)
  3. challenging, intriguing - disturbingly provocative; "an intriguing smile"
    Antonyms: unprovocative, unprovoking (indirect, via provocative)
,Verb challenge has 4 senses
  1. challenge, dispute, gainsay - take exception to; "She challenged his claims"
    --1 is one way to contest, contend, repugn
    Derived form: noun challenge3
    Sample sentences:
    Somebody ----s something
    Somebody ----s somebody
  2. challenge - issue a challenge to; "Fischer challenged Spassky to a match"
    --2 is one way to
    invite, bid
    Derived forms: noun challenger1, noun challenge2
    Sample sentence:
    They challenge him to write the letter
  3. challenge - ask for identification; "The illegal immigrant was challenged by the border guard"
    --3 is one way to
    request, bespeak, call for, quest
    Derived form: noun challenge5
    Sample sentence:
    Somebody ----s somebody
  4. challenge, take exception - raise a formal objection in a court of law
    --4 is one way to object
    Derived form: noun challenge4
    Sample sentence:
    Somebody ----s PP