To call something into question or dispute.
To question or demand the countersign from (one who attempts to pass the lines).
To dare (someone).
To invite (someone) to take part in a competition.
To be difficult or challenging for.
To object to the reception of the vote of, e.g. on the ground that the person is not qualified as a voter.
To take (a final exam) in order to get credit for a course without taking it.
To make a formal objection to a juror.
To dispute (something).
The act of appealing a ruling or decision of a court of administrative agency.
An antagonization or instigation intended to convince a person to perform an action they otherwise would not.
A bid to overcome something.
The act of seeking to remove a judge, arbitrator, or other judicial or semi-judicial figure for reasons of alleged bias or incapacity.
An act of seeking to have a certain person be declared not legally qualified to vote, made when the person offers their ballot.
The act of a sentry in halting a person and demanding the countersign, or (by extension) the action of a computer system demanding a password, etc.
A summons to fight a duel; also, the letter or message conveying the summons.
A difficult task, especially one that the person making the attempt finds more enjoyable because of that difficulty.
An attempt to take possession; a tackle.
An attempt to have a work of literature restricted or removed from a public library or school curriculum.
The opening and crying of hounds upon first finding the scent of their game.
A judge's interest in the result of a case, constituting grounds for them to not be allowed to sit the case (e.g., a conflict of interest).
To question or call into doubt.
To ask a question.
To send a private message to (a user on IRC).
To send out a query letter.
To pass a set of instructions to a database to retrieve information from it.
To ask, inquire.
A question mark.
A question, an inquiry (US), an enquiry (UK).
A set of instructions passed to a database.