If you're so scared of germs that you aren't able to shake people's hands or touch doorknobs, you can call yourself phobic. People who are phobic have strong, irrational fears.
A fear that isn't based in reality is a phobia, and someone who has this kind of fear is phobic. It's not uncommon to be phobic of heights, airplanes, snakes, or the dark. Being phobic goes beyond a dislike or mild anxiety, though — if you're truly phobic of something, you're sometimes unable to face it without trembling or feeling your heart race. The Greek root, phobos, means "fear."