Yes, ARGUMENTS is a Scrabble word!

Letter values in Scrabble US: A 1, R 1, G 2, U 1, M 3, E 1, N 1, T 1, S 1.

Is it a valid word?

ARGUMENTS is a valid word in the official Scrabble dictionary (US), the UK Scrabble Dictionary and Words with Friends (ENABLE).

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

Also: literary argument, logical argument, line of reasoning.

Not playable in Scrabble US: DISCEPTATION.