As a Noun: 1. Thoughts or constant thinking about a problem that you have or about something unpleasant that might happen and the feeling of unhappiness and unease that this causes. English = worry, anxiety, concern. As a Verb or Adjective: 1. To keep thinking about a problem or about something unpleasant that might happen. English = worry, fret; (be) worried, (be) anxious, (be) concerned, (be) fretful.