Yes, RHETORIC is a Scrabble word!

Letter values in Scrabble US: R 1, H 4, E 1, T 1, O 1, R 1, I 1, C 3.

Is it a valid word?

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

using language effectively to please or persuade
high-flown style; excessive use of verbal ornamentation
loud and confused and empty talk
study of the technique and rules for using language effectively (especially in public speaking)

Also: hot air, empty words, empty talk.