The fear of getting in shape by way of exercise and dieting. The fear of lifestyle changes and sacrifice it will take to achieve a healthy body weight.
Fear of in-shape people
Miranda is Morbidly Obese and suffering from multiple auto-immune diseases but her fitphobia keeps her from making lifestyle changes to remedy her situation
Dale is fitphobic and that keeps him from going into the gym even though he has a membership.
The act of being new to guitar hero and being afraid of the blue and orange frets because you don't think your pinky finger can take it. The normal reactions to this are anger, threats, violence, and, depending on how drunk the player is, incessant giggling. Symptoms may include reluctance, making up excuses not to play, and headbanging to draw attention from the T.V.
Danny: Oh crap... here comes the solo...
*guitar squeaks*
Everyonewatching: *laughing*
Danny: Crap! I told you guys I had Fretaphobia! I'm NEVER PLAYING AGAIN!