babysit

Short definition from Wiktionary

Verb

1. 1
   To watch or tend someone else's child for a period of time, often for money.
2. 2
   To watch or tend a thing or process without normally intervening in it, e.g. as a precaution should an emergency happen.
3. 3
   To watch or attend anything or anyone more closely than ought to be needed; to have to help or coax too much.