Nouns:
* watchdog: A person or group that monitors and protects against wrongdoing.
* watchtower: A tower used for observation.
* watchmaker: A person who makes or repairs watches.
* watchband: A strap worn on the wrist to hold a watch.
* watchword: A slogan or motto.
* watchlist: A list of people or things that are being monitored.
* watchful: Being alert and attentive.
Verbs:
* watch out: Be careful or cautious.
* watch over: To guard or protect.
Adjectives:
* watchful: Alert and attentive.
Let me know if you'd like to see more examples or compound words with a different starting word!