Humanoid can be an adjective and a noun.
Adjective: Having the characteristics of a human.
Noun: A being having the characteristics of a human.
Yes, the three types of humanoid aliens are humanoid, non-humanoid and semi-humanoid.
The part of speech for this particular word is a noun.
part of speech
The part of speech for "answer" is a noun.
adverb
what part of speech is beneath
The part of speech for "unfamiliar" is an adjective.
The part of speech of "came" is a verb.
The part of speech for "twirl" is a verb.
The part of speech for "explicit" is an adjective.
The part of speech for "indefinite" is an adjective.
The part of speech for "lecturer" is a noun.