"절대, 결코, 아예, and 전혀"
The words differ somewhat in connotation, nuance and usage. Some can only be used in negative sentences.
- 절대(로): literally "absolute(ly)". At all costs; no matter what. Used in negative (more common) and positive contexts.
- 결코: lit. "with a strong determination". Similar to 절대로 but only used in negative contexts.
- 아예: Fully; in a completely different way. Decisively. Without compromise. Used in positive and negative contexts.
- 전혀: Completely. By no means. At all. Only in negative contexts.
Examples:
- 절대로 그렇겐 하지 못한다: I won't [can't] do that no matter what.
- 이 일은 절대로 성공해야만 한다: We absolutely must succeeded in this.
- 결코 그대를 잊지 않을 것이오: I swear I will never forget you.
- 나쁜 짓은 아예 할 생각을 마라: Don't even think (a moment) of committing something bad.
- 계속 고칠 게 아니라 아예 허물고 다시 짓자: Instead of fiddling with repairs, let's tear the whole thing down and rebuild it.
- 그것은 전혀 사실이 아닙니다: That is completely not true.