1) Challenging question 2) Challenging reply 3) Response to a refusal 4) What do you have to lose 
• (n.) A violent and peremptory procedure without any assigned reason; a sudden conclusive happening.
Why'-not` noun A violent and peremptory procedure without any assigned reason; a sudden conclusive happening. [ Obsolete] « When the church Was taken with a why-not in the lurch.» Hudibras. « This game . . . was like to have been lost with a why- not .»