dare
noun
a challenge to do something dangerous or foolhardy
“he could never refuse a dare”
Synonymsdaring
verb
take upon oneself; act presumptuously, without permission
“How dare you call my lawyer?”
to be courageous enough to try or do something
“I don't dare call him”
“she dares to dress differently from the others”
challenge
“I dare you!”
Synonymsdefy
Source: WordNet 3.1, Princeton University