Dismissal is a noun.
Adjective: The girl is very dismissive. The girl is very tall. Both can be used the same way because they are both adjectives.
She was dismissive of trying new things.
part of speech
The part of speech for this particular word is a noun.
The part of speech for "answer" is a noun.
adverb
what part of speech is beneath
The part of speech for "explicit" is an adjective.
The part of speech for "twirl" is a verb.
The part of speech for "unfamiliar" is an adjective.
The part of speech of "came" is a verb.
The part of speech for "lecturer" is a noun.