Yes, rip is a Scrabble word!
...and is worth 5 points in Scrabble, and 6 points in Words with Friends
rip
Verb
1. Tear or be torn violently
2. Move precipitously or violently
3. Cut (wood) along the grain
4. Criticize or abuse strongly and violently
Noun
1. A dissolute man in fashionable society
2. An opening made forcibly as by pulling apart
3. A stretch of turbulent water in a river or the sea caused by one current flowing into or across another current
4. The act of rending or ripping or splitting something
What Scrabble words can I make with the letters in rip?
2 Letter Words