Is artist a word in the Scrabble Dictionary

Yes, artist is playable

...and is worth 6 points.

Found in the following dictionaries

Enable (Words with friends)
SOWPODS (Collins Scrabble Words)
OTCWL2014 (NASPA Word List 2014)
TWL06 (NASPA List 2006)

"Artist" Definition

noun

A person whose work shows exceptional creative ability or skill: You are an artist in the kitchen.
One who is adept at an activity, especially one involving trickery or deceit: a con artist.
One, such as a painter, sculptor, or writer, who is able by virtue of imagination and talent or skill to create works of aesthetic value, especially in the fine arts.
One, such as an actor or singer, who works in the performing arts.
One skilled or versed in learned arts.