dare 
(dâr)
(dâr)v. dared, dar·ing, dares
v.tr.
1. To have the courage required for: The gymnast dared a breathtakingly difficult move.
2. To challenge (someone) to do something requiring boldness: They dared me to dive off the high board.
3. To confront boldly; brave: dared the dizzying heights of the mountain. See Synonyms at defy.
v.intr.
To be courageous or bold enough to do or try something: Go ahead and dive if you dare.
v.aux.
To be courageous or bold enough to: I dare not say. How dare she go?
n.
An act of daring; a challenge.
[Middle English daren, from Old English dearr, first and third person sing. present indicative of durran, to venture, dare; see dhers- in the Appendix of Indo-European roots.]
darer n.
Usage Note: Depending on its sense, the verb dare sometimes behaves like an auxiliary verb (such as can or may) and sometimes like a main verb (such as want or try). When used as an auxiliary verb, dare does not change to agree with its subject: He dare not do that again. It also does not combine with do in questions, negations, or certain other constructions: Dare we tell her the truth? I dare not mention their names. Finally, it does not take to before the verb that follows it: If you dare breathe a word about it, I'll never speak to you again. When used as a main verb, dare does agree with its subject (If he dares to show up at her house I'll be surprised), and it does combine with do (Did anyone dare to admit it?). It may optionally take to before the verb following it: No one dares (or dares to) speak freely about the political situation. The auxiliary forms differ subtly in meaning from the main verb forms in that they emphasize the attitude or involvement of the speaker while the main verb forms present a more objective situation. Thus How dare you operate this machinery without proper training? expresses indignation at the action, whereas How do you dare to operate this machinery without proper training? is a genuine request for information. When dare is used as a transitive verb meaning "challenge," only main verb forms are possible and to is required: Anyone who dares him to attempt it will be sorry.