argument vs clincher

argument and clincher both are nouns.

Word	Noun	Adjective	Verb	Adverb
argument	Yes	No	No	No
clincher	Yes	No	No	No

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

argument (noun)	clincher (noun)
a variable in a logical or mathematical expression whose value determines the dependent variable; if f(x)=y, x is the independent variable	a tool used to clinch nails or bolts or rivets
a course of reasoning aimed at demonstrating a truth or falsehood; the methodical process of logical reasoning	a point or fact or remark that settles something conclusively
a discussion in which reasons are advanced for and against some proposition or proposal	an argument that is conclusive
a summary of the subject or plot of a literary work or play or movie
a fact or assertion offered as evidence that something is true
a contentious speech act; a dispute where there is strong disagreement
(computer science) a reference or value that is passed to a function, procedure, subroutine, command, or program