Adverbs

In general, many adverbs, called 부사 in Korean, are created by attaching 게 to to the end of an adjective stem (A + 게). However, sometimes there is a more natural form, especially adverbs ending with the syllable 히 or (으)로. Also since Korean and English are quite different languages, some of the adverbs translated literally into English can sound awkward, for example '맛있게 먹다' means eat deliciously.

Common Adverbs Formed with Adjective + 게

Also see: A + 게

Adverbs formed using adjective + 게

Adjective (descriptive verb)	Meaning	Adverb form	Meaning
가볍다	to be light	가볍게	lightly
나쁘게	to be bad	나쁘게	badly
늦다	to be late	늦게	late (adv)
맛있다	to be delicious	맛있게	deliciously
무례하다	to be rude	무례하게	rudely
바쁘다	to be busy	바쁘게	busily
밝다	to be bright	밝게	brightly
싸다	to be cheap	싸게	cheaply
아름답다	to be beautiful	아름답게	beautifully
안전하다	to be safe	안전하게	safely
어렵다	to be difficult	어렵게	difficultly
이쁘다	to be pretty	이쁘게	prettily
용기 있다	to have courage	용기있게	bravely, courageously
위험하다	to be dangerous	위험하게	dangerously
자연스럽다	to be natural	가연스럽게	naturally
자유롭다	to be free	자유롭게	freely
재미있다	to be fun	재미있게
조용하다	to be quiet	조용하게	quietly
즐겁다	to be pleasant	즐겁게	pleasantly
크다	to be large	크게	largely
편리하다	to be convenient	편리하게	conveniently
편하다	to be comfortable	편하게	comfortably
행복하다	to be happy	행복하게	Happily

Common Adverbs Ending with 히

Adjectives Ending with 히

Adverb	Meaning	Derived from	Meaning
대단히	greatly, highly, extremely	대단하다	to be great, incredible
분명히	definitely, clearly, certainly	분명하다	to be clear
솔직히	honestly, frankly	솔직하다	to be frank, honest, open
순순히	passively, obediently	순순하다	to be passive, obedient
열심히	zealously, hard (i.e. work hard)
완전히	completely, fully, perfectly	완전하다	to be complete, full, perfect
우연히	on accident, by chance	우연하다	to be accidental, coincidental
자세히	in detail	자세하다	to be detailed
천천히	slowly	N/A
특히	especially, particularly	특별하다	to be special
확실히	certainly, for sure, for certain, definitely	확실하다	to be certain, sure

Korean seldom use "천천한" so don't regard it as mechanical thing.
Some words originated from Chinese Character, like English word with Latin or Greek dervation. That's why you may have some difficulty in finding relation between "특히" & "특별한"
There's some applications of "특". "특식" - special food "특실" - special room "특차" - specially selected and uncountable applications because Chinese charcter has its own meaning and various combinations are possible.

Common Adverbs Ending with (으)로

These are often formed with nouns, sometimes in conjunction with 적 attached to the noun as well.

Adjectives Ending with (으)로

Noun or derivative	Meaning	Adverb	Meaning
일반	general	일반적으로	generally
자동	automatic	자동으로	automatically
공식		공식적으로	formally, officially
비공식		비공식적으로	informally, unofficially
협동		협동적으로	cooperatively
주기		주기적으로	regularly
장기		장기적으로	in the long term
단기		단기적으로	in the short term
상식		상식적으로	using common sense, through common sense
사적	personal	사적으로	personally
적극		적극적으로	enthusiastically, actively, aggressively
획기		획기적으로	innovatively
극	drama	극적으로	dramatically
기적	miracle	기적적으로	miraculously
전적		전적으로	completely, totally, entirely
상대	relativity	상대적으로	relatively
잠정		잠정적으로	tentatively
물리	physics	물리적으로	physically
심리	psychology	심리적으로	psychologically
질적	qualitative	질적으로	qualitatively
고질		고질적으로	chronically
기본	fundamental	기본적으로	fundamentally
본능	instinct	본능적으로	instinctively
수동	manual	수동으로	manually
의도	intention	의도적으로	intentionally, on purpose
억지		억지로	by force, forcibly, against one's will
구체적	detailed	구체적으로	in detail

Other Adverbs

• 직접 - in person
• 없이 - without
  • 틀림 없이 - Certainly, sure, definitely, no matter what. Literally means 'without error' or 'without a mistake.'
• 빨리 - quickly 빠른 is quick, and 빨리 is just similar changing.
• 많이 - many
• 일찍 - early
• 같이 - with, together. 같은 means same. If people has common mind, they could be together.

That's why Korean usually say "우리 아빠" (our dad) instead of "내 아빠" (my dad). Korean has more concern about concept of community, though it is becoming more influenced by western style individualism.

• 따로 - separately. It comes from 다른 (different).
• 깊이 - deeply. 깊은 is adjective/modifier.
• 갑자기 - suddenly. 갑작스런 is adjective.
• 꼭 - for sure
• 반드시 - at all cost, no matter what
• 보통 - usually
• 전혀 - never
• 만날 - every day. More often pronounced and used as 맨날.
• 자주 - often, frequently.
• 자꾸 - continuously often; 자꾸 is something to do with obsession.
  • "자꾸 니 생각이나" (I can't stop thinking about you)
• 가끔 - sometimes, occasionally, once in a while.
• 일부러 - on purpose, deliberately
• 함부로 - carelessly, mindlessly