fall vs sink

fall and sink both are nouns.

Word	Noun	Adjective	Verb	Adverb
fall	Yes	No	Yes	No
sink	Yes	No	Yes	No

As verbs, sink is a hyponym of fall; that is, sink is a word with a more specific, narrower meaning than fall:

fall (noun)	sink (noun)
a sudden drop from an upright position	plumbing fixture consisting of a water basin fixed to a wall or floor and having a drainpipe
the act of surrendering (usually under agreed conditions)	a covered cistern; waste water and sewage flow into it
a lapse into sin; a loss of innocence or of chastity	a depression in the ground communicating with a subterranean passage (especially in limestone) and formed by solution or by collapse of a cavern roof
a sudden sharp decrease in some quantity	(technology) a process that acts to absorb or remove energy or a substance from a system
a free and rapid descent by the force of gravity
a sudden decline in strength or number or importance
when a wrestler's shoulders are forced to the mat
a movement downward
a downward slope or bend
the season when the leaves fall from the trees
the time of day immediately following sunset

fall (verb)	sink (verb)
occur at a specified time or place	fall heavily or suddenly; decline markedly
decrease in size, extent, or range	embed deeply
pass suddenly and passively into a state of body or mind	go under
be born, used chiefly of lambs	fall or descend to a lower place or level
come out; issue	cause to sink
assume a disappointed or sad expression	fall or sink heavily
begin vigorously	appear to move downward
come as if by falling	descend into or as if into some soft substance or place
be cast down	pass into a specified state or condition; sink into
go as if by falling
fall or flow in a certain way
move downward and lower, but not necessarily all the way
move in a specified direction
descend in free fall under the influence of gravity
slope downward
drop oneself to a lower or less erect position
lose an upright position suddenly
to be given by assignment or distribution
be captured
fall to somebody by assignment or lot; passed
come into the possession of
to be given by right or inheritance
be inherited by
lose office or power
yield to temptation or sin
suffer defeat, failure, or ruin
lose one's chastity
die, as in battle or in a hunt
be due
come under, be classified or included
touch or seem as if touching visually or audibly
fall from clouds