jackknife vs athletics

jackknife and athletics both are nouns.

Word	Noun	Adjective	Verb	Adverb
jackknife	Yes	No	Yes	No
athletics	Yes	No	No	No

jackknife (noun)	athletics (noun)
a dive in which the diver bends to touch the ankles before straightening out	an active diversion requiring physical exertion and competition
a large knife with one or more folding blades	participation in sports events as an extracurricular activity
	a contest between athletes

jackknife (verb)	athletics (verb)
dive into the water bending the body at the waist at a right angle, like a jackknife