What part of speech is “best”
Noun
Definition:
as a noun, 'best' refers to the most excellent or desirable type or quality.
Examples:
She is the best of the two players.
The best is yet to come.
At his best, he is an excellent performer.
Tips:
When used as a noun, 'best' often appears in the phrase 'the best of' to specify what it is being compared to.
Adjective
Definition:
as an adjective, 'best' is the superlative form of 'good,' and it is used to describe something that is of the highest quality, excellence, or suitability among three or more entities.
Examples:
She is the best student in the class.
This is the best book I've ever read.
The best way to learn is by doing.
Tips:
'Best' is irregular; do not use it as 'most good.' Avoid using 'best' to compare only two things; for that, the word 'better' is appropriate.
Adverb
Definition:
As an adverb, 'best' modifies a verb, adjective, or another adverb to indicate that something is done in the most excellent or effective manner possible.
Examples:
She sings best.
He runs best when he's relaxed.
You learn best by doing.
Tips:
When used as an adverb, 'best' usually doesn't require 'the,' but the comparison is usually understood.