extremely

As an adverb extremely

is (degree) to an extreme degree.

As an adjective undefined is

lacking a definition or value.

As adverbs the difference between extremely and massively

is that extremely is (degree) to an extreme degree while massively is in a massive manner, in a way that appears large, heavy or imposing.

As adverbs the difference between abit and extremely

is that abit is while extremely is (degree) to an extreme degree.

As an adverb extremely

is (degree) to an extreme degree.

As an adjective strenuous is

urgent, ardent, zealous.

As adverbs the difference between heavily and extremely

is that heavily is in a heavy manner while extremely is (degree) to an extreme degree.

As a proper noun supreme

is the supreme being; the almighty; god.

As an adverb extremely is

(degree) to an extreme degree.

As adverbs the difference between overtly and extremely

is that overtly is in an overt manner; publicly; openly while extremely is (degree) to an extreme degree.

As an adverb extremely

is (degree) to an extreme degree.

As an adjective crucial is

being essential or decisive for determining the outcome or future of something; extremely important.

As adverbs the difference between pretty and extremely

is that pretty is somewhat, fairly, quite; sometimes also (by meiosis) very while extremely is (degree) to an extreme degree.

As an adjective pretty

is cunning; clever, skilful.

As a noun pretty

is something that is pretty.

As a verb pretty

is to make pretty; to beautify.