baffle

Concise Oxford English Dictionary © 2008 Oxford University Press:
baffle/ˈbafl/

▶verb

• 1 totally bewilder.

• 2 restrain or regulate (a fluid, a sound, etc.).

▶noun a device used to restrain the flow of a fluid, gas, or loose material or to prevent the spreading of sound or light in a particular direction.

– derivatives
bafflement noun,
baffler noun,
baffling adjective,
bafflingly adverb.

– origin C16 (in the sense ‘cheat, deceive’): perh. rel. to Fr. bafouer ‘ridicule’ or obs. Fr. beffer ‘mock, deceive’.