Yes, lapse is a Scrabble word!

Verb

1. Pass into a specified state or condition

2. End, at least for a long time

3. Drop to a lower level, as in one's morals or standards

4. Go back to bad behavior

5. Let slip

6. Pass by

Noun

1. A mistake resulting from inattention

2. A break or intermission in the occurrence of something

3. A failure to maintain a higher state