No, harmful is an adjective.
A verb is a word that describes an action (run, walk, etc), a state of being (exist, stand, etc) or occurrence (happen, become, etc).
An adjective is a word that describes a noun (the car is blue / it was a cold day / etc).
A noun is a word that is used to describe a person (man, lady, teacher, etc), place (home, city, beach, etc) or thing (car, banana, book, etc).
"clear-cutting" The verb is always the doing word
the crept in the house is very harmful.
The word 'pollution' is not a verb. The word pollution is a noun, a word for a substance in the environment that is harmful; a word for a thing. The verb forms are: pollute, pollutes, polluting, polluted The verb to pollute is a main verb.
The word "abuse" can function as both a noun and a verb. As a noun, it refers to the improper or harmful treatment of something or someone. As a verb, it means to use something in a harmful or improper way.
"The detrimental dog kicked the harmful kitty" is a sentence - there is a subject (dog) and a verb (kicked).
The verb of abuse is 'to abuse...' e.g. to abuse the law
No, "poisonous" is an adjective that describes something that is harmful or toxic. The verb form would be "poison."
The word 'harmful' is not a noun.The word 'harmful' is an adjective, a word used to describe a noun.The noun form of the adjective 'harmful' is harmfulness.The word 'harmful' is the adjective form of the noun harm.The nouns 'harmfulness' and 'harm' are both common, uncountable (mass), abstract nouns; words for concepts.The word 'harm' is also a verb: harm, harms, harming, harmed.
Pollution is the abstract noun.
The noun 'is' is a verb, a form of the verb 'to be'. The verb 'is' functions as an auxiliary verb and a linking verb.
It is a Linking Verb. The word are is a conjugation of the verb "to be."
It is an action verb.