A worrywart is someone who is overly anxious and worries excessively about things. The term can be broken down into four other words: PESSIMIST (9 letters), stewer (6 letters), fusser (6 letters), and FUSSPOT (7 letters). A PESSIMIST is someone who expects the worst outcome in any situation. A stewer is someone who worries and frets over something. A fusser is someone who complains or makes a fuss about something. A FUSSPOT is someone who is easily irritated and prone to complaining. Finally, a nervous Nellie is someone who is very anxious and easily scared.