'largest' is a superlative form of the adjecitve 'large.' Its role as an adjective in the English language is to describe something that is of the greatest magnitude or measure when comparing to other items.
the rules and use cases associated with the word when used as an adjective include an article ‘the’ before the word and a noun describing what the word ‘largest’ is referring to after the word.
He lives in the largest house on the block.
This is the largest number in the series.
Mount Everest is the largest mountain in the world
a common mistake that is often made when using the word ‘largest’ as an adjective is to forget to add the article ‘the’ before the word.