Yes, oath is a Scrabble word!
...and is worth 7 points in Scrabble, and 6 points in Words with Friends
oath
Noun
1. Profane or obscene expression usually of surprise or anger
2. A commitment to tell the truth (especially in a court of law); to lie under oath is to become subject to prosecution for perjury
3. A solemn promise, usually invoking a divine witness, regarding your future acts or behavior
What Scrabble words can I make with the letters in oath?
3 Letter Words
2 Letter Words