stifle

Concise Oxford English Dictionary © 2008 Oxford University Press:
stifle1

▶verb

• 1 prevent from breathing freely; suffocate.

• 2 smother or suppress: she stifled a giggle.

  ■ prevent or constrain (an activity or idea).

– derivatives
stifler noun,
stifling adjective,
stiflingly adverb.

– origin ME: perh. from a frequentative of OFr. estouffer ‘smother, stifle’.

Concise Oxford English Dictionary © 2008 Oxford University Press:
stifle2

▶noun a joint in the legs of horses, dogs, and other animals, equivalent to the knee in humans.

– origin ME: of unknown origin.