The correct medical term for someone exercise obsessed is 'physically attractive'.
A Hypochondriac.
Hydromaniac
A person who is obsessed with dates is called a "chronophile."
Grammar Nazi
"Otaku", "Weeb", or "Weeaboo".
Well it depends. If you're a man and you're obsessed with another man well it's called being gay. And if you're a girl and you're obsessed with men it's called love!
A person that loves all things French might be called a Francophile.
A person who is obsessed with book is a bibliophile.
a foot fetish (podophilia). A person with podophilia is a podophile (not to be confused with pedophile).
It is called pyromania. The person is a pyromaniac, or firebug.
an obsessed person is somebody who only thinks of one thing and does it all the time
A person that hunts dinosaur bones is called a paleontologist.
lexicologist.