Vitriolic is an adjective.
The vitriolic speech was followed by the cancellation of the summit meeting. The mayor faced vitriolic denunciations from his own party after proposing new taxes.
His answer was vitriolic, and I drew back, surprised by his caustic tone.
His answer was vitriolic, so he got better scores than me
vitriolic = harsh, bitterly scathing or caustic in tone eg The book was so bad that the criticism was vitriolic
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.