Is attack a common noun

Answer 1

No because a compound word is made when two words are joined to form a new word. Attack might have at and tack. All compound words must have two words and no remaining letters. Attack doesn't have any but it is not a compound word.

Answer 2

Yes, the noun 'attack' is a common noun, a general word for an organized attempt to defeat an enemy; a violent attempt to harm someone or something; harsh criticism; an episode of a disease or physical problem; a general word for a thing.

The word 'attack' is also a verb: attack, attacks, attacking, attacked.