Is buzzing an adjective or verb?

Answer 1

The word 'buzzing' is an adjective, a verb, and a noun. The word buzzing is the present participle of the verb 'to buzz'. The present participle is also an adjective and a gerund (verbal noun). Examples:

Adjective: I hear a buzzing sound.

Verb: The sun is shinning, the bees are buzzing, it's a fine summer day.

Noun: That buzzing is very distracting.

Answer 2

No. It is a past tense form of the verb "to buzz."

Answer 3

The word buzzed is an adjective.

It is also a verb in that it is the past tense of "buzz".