thorax vs male chest

thorax and male chest both are nouns.

Word	Noun	Adjective	Verb	Adverb
thorax	Yes	No	No	No
male chest	Yes	No	No	No

As nouns, male chest is a hyponym of thorax; that is, male chest is a word with a more specific, narrower meaning than thorax:

thorax: the part of the human torso between the neck and the diaphragm or the corresponding part in other vertebrates
male chest: the chest of a man

Other hyponyms of thorax include bust, female chest.

thorax (noun)	male chest (noun)
part of an insect's body that bears the wings and legs	the chest of a man
the part of the human torso between the neck and the diaphragm or the corresponding part in other vertebrates
the middle region of the body of an arthropod between the head and the abdomen