phlegmatic
Meaning: uninterested, unresponsive
Usage: Monique feared her dog was ill after the animal’s phlegmatic response to his favorite chew toy.
perfunctory
Meaning: showing little interest or enthusiasm
Usage: The clerk gave a perfunctory greeting without looking up.
disheartened
Meaning: feeling a loss of spirit or morale
Usage: The team was disheartened after losing in the finals of the tournament.
despondent
Meaning: feeling depressed, discouraged, hopeless
Usage: Having failed the first math test, the despondent child saw no use in studying for the next and failed that one too.
apathetic
Meaning: lacking concern, emotion
Usage: Uninterested in politics, Bruno was apathetic about whether he lived under a capitalist or communist regime.