Dare (9)
'dare' is the definition.
(I know that dare is a more specific form of the action challenge)
This is the entire clue.
(Other definitions for challenge that I've seen before include "Dare - raise an objection" , "Ask to take part in a contest" , "Question truth of - dare" , "Invite to contest, throw down the gauntlet" , "tackle" .)
'dare' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for venture that I've seen before include "'Nothing . . . . . . ., nothing gain'" , "Risk or take a chance on" , "Undertake a risky course of action" , "Put at risk" , "Commercial undertaking that risks a loss but promises a profit" .)