Yes, jars is a Scrabble word!
...and is worth 11 points in Scrabble, and 13 points in Words with Friends
jars
Verb
1. Be incompatible; be or come into conflict
2. Move or cause to move with a sudden jerky motion
3. Shock physically
4. Affect in a disagreeable way
5. Place in a cylindrical vessel
Noun
1. A vessel (usually cylindrical) with a wide mouth and without handles
2. The quantity contained in a jar
3. A sudden jarring impact
What Scrabble words can I make with the letters in jars?
3 Letter Words
2 Letter Words