unbetterable

As a noun terms

is .

As an adjective unbetterable is

that cannot be bettered.

As adjectives the difference between better and unbetterable

is that better is (good) while unbetterable is that cannot be bettered.

As an adverb better

is .

As a verb better

is to improve.

As a noun better

is an entity, usually animate, deemed superior to another; one who has a claim to precedence; a superior or better can be .