Gordian knot
abecedarian
addle
amaze
answer
answer conclusively
argue down
astonish
astound
baffle
bafflement
balk
bamboozle
beat
bewilderment
blast
boggle
bother
brave
bring up short
buffalo
challenge
check
checkmate
circumvent
confound
confoundment
confront
confuse
confusion
confute
contradict
contravene
controvert
counter
counteract
countermand
counterwork
cross
crush
crux
dabbler
dash
daze
defeat
defy
demolish
deny
nonplussed
nonplusses
nonplussing
nonpluss
blankest
self-involved
sleepy-eyed
enlighten