The crossword solution for the term 'TENSED, WITH 'UP'' is KEYED. This term is used to describe a situation in which someone is feeling anxious or nervous. It is often used to describe a feeling of being on edge or having a heightened sense of awareness. The phrase 'keyed up' is used to describe this feeling, and it is derived from the idea of a key turning in a lock, which is a metaphor for the feeling of tension.