Demolished is a verb (past tense of demolish) and an adjective (a demolished building).
The antonym for 'demolish' is 'construct'
demolish = a demola
part of speech
'Prepare' is not the opposite of 'demolish'; 'build' or 'construct' are two words that are opposites of 'demolish'.
An adjective is a part of speech.
what part of speech is beneath
The part of speech is a adjective
adverb
what part of speech is work
The man had to demolish the car in thirty seconds.
The part of speech which "antagonist" is, is noun.