Yes, cult is a Scrabble word!
...and is worth 6 points in Scrabble, and 9 points in Words with Friends
cult
Noun
1. Followers of an exclusive system of religious beliefs and practices
2. An interest followed with exaggerated zeal
3. Followers of an unorthodox, extremist, or false religion or sect who often live outside of conventional society under the direction of a charismatic leader
4. A religion or sect that is generally considered to be unorthodox, extremist, or false
5. A system of religious beliefs and rituals
What Scrabble words can I make with the letters in cult?
3 Letter Words
2 Letter Words