Definition of stifles:
(v) :
(transitive, also figuratively) To make (an animal or person) unconscious or cause (an animal or person) to die by preventing breathing; to smother, to suffocate.
(v) :
(transitive, hyperbolic) To cause (someone) difficulty in breathing, or a choking or gagging feeling.
(v) :
(transitive, also figuratively) To prevent (a breath, cough, or cry, or the voice, etc.) from being released from the throat.
(v) :
(transitive, figuratively) (transitive) To keep in, hold back, or repress (something).
(v) :
(transitive, figuratively) (transitive) To prevent (something) from being revealed; to conceal, to hide, to suppress.
(v) :
(transitive) To make (something) unable to be heard by blocking it with some medium.