puzzle.

[vidyaksri]

I am a 9 letter thing.teacher hates me.Cow likes me.Monkey eats me.who am i?

[Tewart]

Found this answer elsewhere on the web:

The answer is tautonyms, which is considered to be any word or term made from two identical parts or syllables.
The teacher hate me... because tautonyms are no longer allowed in botany
the cow like me... Bison bison is tautonym for American Bison
Monkey want to eat me...Ziziphus zizyphus is tautonym for jujube, a fruit-flavored, usually chewy candy or lozenge, liked by monkey.