Yes, sneaks is a Scrabble word!

Verb

1. To go stealthily or furtively

2. Put, bring, or take in a secretive or furtive manner

3. Make off with belongings of others

4. Pass on stealthily

Noun

1. A person who is regarded as underhanded and furtive and contemptible

2. Someone who prowls or sneaks about; usually with unlawful intentions

3. Someone acting as an informer or decoy for the police