1) Absolutely 2) Amazingly 3) Astonishingly 4) Awfully 5) Completely 6) Decidedly 7) Dreadfully 8) Enormously 9) Especially 10) Ever so 11) Exceedingly 12) Exceptionally 13) Extraordinarily 14) Fantastically 15) Greatly 16) Highly 17) In an extreme degree 18) Incredibly 19) No end 20) Particularly 21) Really 1) All-fired 2) Bloody 3) Boiling 4) Damn 5) Damned 6) Dangerously 7) Deadly 8) Deeply 9) Desperately 10) Deucedly 11) Devilishly 12) Enormously 13) Ever so 14) Exceedingly 15) Extraordinarily 16) Fabulously 17) Fantastically 18) Goddam 19) Goddamn 20) Goddamned 21) Hellishly 22) Highly 23) Hugely 24) Incredibly 
• (adv.) In an extreme manner or state; in the utmost degree; to the utmost point; exceedingly; as, extremely hot or cold.
Ex·treme'ly adverb In an extreme manner or state; in the utmost degree; to the utmost point; exceedingly; as, extremely hot or cold. 
[adv] - to an extreme degree
adverb to an extreme degree; `extremely cold`; `extremely unpleasant`
in an extreme degree; exceedingly: extremely cold.