sti·fle1 / ˈstīfəl/ • v. [tr.] 1. make (someone) unable to breathe properly; suffocate: those in the streets were stifled by the fumes | [as adj.] (stifling) stifling heat. 2. restrain (a reaction) or stop oneself acting on (an emotion): she stifled a giggle she stifled a desire to turn and flee| [as adj.] (stifled) she gave a stifled cry of disappointment. ∎ prevent or constrain (an activity or idea): high taxes were stifling private enterprise.DERIVATIVES: sti·fler / -f(ə)lər/ n.sti·fling·ly / -f(ə)linglē/ adv. a stiflingly hot day. sti·fle2 (also sti·fle joint) • n. a joint in the legs of horses, dogs, and other animals, equivalent to the knee in humans.