I have a phobia of shots, and I don’t know how I ended up with this fear of injections. So the definition of a phobia is an extreme or irrational fear of or aversion to something. Out of curiosity I looked up the term for mine. Trypanophobia, is the fear involving injections of hypodermic needles and is rarely used; while aichmophobia, belonephobia, or enetophobia are other terms for it. However, the last three terms are more directed toward the fear of sharp objects in general.