bend vs kink

bend and kink both are nouns.

Word	Noun	Adjective	Verb	Adverb
bend	Yes	No	Yes	No
kink	Yes	No	Yes	No

As nouns, kink is a hyponym of bend; that is, kink is a word with a more specific, narrower meaning than bend:

bend: an angular or rounded shape made by folding
kink: a sharp bend in a line produced when a line having a loop is pulled tight

Other hyponyms of bend include plait, pleat, twirl, twist, pucker, ruck, accordion fold, concertina fold, z-fold, zig-zag fold.

bend (noun)	kink (noun)
curved segment (of a road or river or railroad track etc.)	a difficulty or flaw in a plan or operation
diagonal line traversing a shield from the upper right corner to the lower left	an eccentric idea
movement that causes the formation of a curve	a person with unusual sexual tastes
an angular or rounded shape made by folding	a sharp bend in a line produced when a line having a loop is pulled tight
a circular segment of a curve	a painful muscle spasm especially in the neck or back (`rick' and `wrick' are British)

bend (verb)	kink (verb)
cause (an object) to assume a crooked or angular form	form a curl, curve, or kink
bend a joint	curl tightly
form a curve
change direction
turn from a straight course, fixed direction, or line of interest
bend one's back forward from the waist on down