stifle vs obstruct

stifle is a noun but obstruct is not a noun.

Word	Noun	Adjective	Verb	Adverb
stifle	Yes	No	Yes	No
obstruct	No	No	Yes	No

As verbs, obstruct is a hypernym of stifle; that is, obstruct is a word with a broader meaning than stifle:

Other hypernyms of stifle include block, close up, impede, jam, obturate, occlude.

stifle (noun)	obstruct (noun)
joint between the femur and tibia in a quadruped; corresponds to the human knee

stifle (verb)	obstruct (verb)
suppress or constrain so as to lessen in intensity	block passage through
be asphyxiated; die from lack of oxygen	shut out from view or get in the way so as to hide from sight
suppress in order to conceal or hide	hinder or prevent the progress or accomplishment of
impair the respiration of or obstruct the air passage of