Yes, thug is a Scrabble word!
...and is worth 8 points in Scrabble, and 9 points in Words with Friends
thug
Noun
1. An aggressive and violent young criminal
What Scrabble words can I make with the letters in thug?
3 Letter Words
2 Letter Words
Noun
1. An aggressive and violent young criminal
3 Letter Words
2 Letter Words