Yes, lather is a Scrabble word!

Verb

1. Beat severely with a whip or rod

2. Form a lather

3. Exude sweat or lather

4. Rub soap all over, usually with the purpose of cleaning

Noun

1. The froth produced by soaps or detergents

2. Agitation resulting from active worry

3. A workman who puts up laths

4. The foam resulting from excessive sweating (as on a horse)