Correct spelling

extremely

Correct spelling, explanation: extremely is the correct form, because here suffix -ly (adverb suffix) was added to the adjective extreme; we do not drop the final e, because -ly starts with a consonant, not a vowel. Extremly is thus an incorrect form, even though pronunciation may point to no e there.

Definition of extremely:
adverb, in an unusual and often dangerous way; also: very much
Next holidays they want to go to an extremely long journey into the Amazon rainforest.
We were extremely excited about the event.


Incorrect spelling

extremly

Incorrect spelling, explanation: This spelling is incorrect since we add an adverb suffix to full form adjectives, therefore extreme plus -ly is extremely, not extremly. The suffix starts with a consonant, which means we do not skip the final e in a word, and because of that the correct form is extremely.

Incorrect spelling

extremley

Incorrect spelling

Incorrect spelling

extremelly

Incorrect spelling

Incorrect spelling

extrimely

Incorrect spelling

Incorrect spelling

extremmely

Incorrect spelling