Yes, PARADIGMS is a Scrabble word!

Letter values in Scrabble US: P 3, A 1, R 1, A 1, D 2, I 1, G 2, M 3, S 1.

Is it a valid word?

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

systematic arrangement of all the inflected forms of a word
a standard or typical example
the class of all items that can be substituted into the same position (or slot) in a grammatical sentence (are in paradigmatic relation with one another)
the generally accepted perspective of a particular discipline at a given time

Also: substitution class.