Challenging - Definition
challenging
adj 1: requiring full use of your abilities or resources;
"ambitious schedule"; "performed the most challenging
task without a mistake" [syn: ambitious, challenging]
2: stimulating interest or thought; "a challenging hypothesis";
"a thought-provoking book" [syn: challenging, thought-
provoking]
3: disturbingly provocative; "an intriguing smile" [syn:
challenging, intriguing]