Herbivore

An herbivore is any animal that eats only plants, such as fruits and vegetables. An herbivore is unlike a vegetarian in that it does not make the conscious choice to not eat meat.

On Earth, the stegosaurus was variety of dinosaur that was strictly a herbivore, a fact that Charles Tucker had to remind Malcolm Reed. 

When captured by the Kzinti in 2269, the Chuft Captain referred to Spock as an herbivore – an eater of "roots and leaves". Because of this classification, the Chuft Captain refused to speak to Spock, and would only speak to Hikaru Sulu, because he at least ate meat.

The Kzinti Telepath found it extremely difficult to read Spock's mind, because he could see images of Spock eating vegetation.