The adjective worried describes someone who's uneasy or troubled about something. Imagine worried parents, up late, waiting for their teenager to arrive home from a party.
Someone with a worried frown on his face always seems concerned. A worried email to your cousin who's traveling in the Middle East expresses your concern for her safety. The root of worried is the Old English word wyrgan, or strangle. It wasn't until the late 1800s that worried was used to describe feeling anxiety.