Someone who's unanimated is lacking liveliness or movement. It's normal for your cactus to be unanimated, but if your kitten is unanimated, you may want to take her to the vet.
The adjective unanimated is useful for describing anyone who's dull or listless, like an unanimated teenager at a family dinner. Something that's still can also be called unanimated, like an old-fashioned, unanimated video game. When you add the prefix un-, "not," to animated (the roots of which trace back to the Latin anima, "life or breath") you get the dreary, lackluster unanimated.