adjective, as in pleasant, redundant, adamant
The word defendant, like many other words (but not all) that end in -ant, is a noun. Another noun that ends in -ant is pendant.Some words that end in -ant are adjectives, like compliant.
The spider and ant may be both invertabretes but the ant is not part of the spider family.
Thorax.
it is along the back part of an ant body
The phrase making a mountain out of an ant hill means turning a big problem out of a small one. It is a figure of speech.
In the middle part of the ant.
part of speech
The part of speech for this particular word is a noun.
what part of speech is beneath
adverb
what part of speech is work