The term 'Jumpy Bug' can be broken down into two crossword solutions: FLEA (4 letters) and NERVOUSTICK (11 letters). A FLEA is a small, wingless insect that feeds on the blood of mammals and birds. Fleas are known for their jumping ability, which is why they are often referred to as 'jumpy bugs'. Nervoustick is an informal term used to describe someone who is easily startled or jumpy. This term is often used to describe people who are anxious or nervous.