기 (nominalization) - Abstract Noun Formation

Using -기 is probably the easiest thing you will do in Korean today. You do not need to worry about whether the verb ends in a consonant or a vowel. There are no complicated batchim rules to memorize here. You simply take the verb or adjective you want to change. You strip away the 다 at the end to find the stem. Then, you attach -기 directly to that stem. That is it. You have just created a noun. For example, 가다 becomes 가기. 읽다 becomes 읽기. Even descriptive verbs (adjectives) work this way. 크다 (to be big) becomes 크기 (size). It is like a universal adapter for your vocabulary.

1. 1Find the dictionary form of the verb or adjective (e.g., 보다, 청소하다, 멀다).
2. 2Remove the 다 suffix to get the stem (보, 청소하, 멀).
3. 3Attach -기 to the end of the stem.
4. 4Result: 보기 (looking/seeing), 청소하기 (cleaning), 멀기 (being far).
5. 5Note: Even for ㄹ irregular verbs like 만들다, you keep the ㄹ. It becomes 만들기.
6. 6Note: For ㅂ irregulars like 춥다, it becomes 춥기. No changes needed!

You will use -기 in four main scenarios. First, it is the king of lists. If you are writing a shopping list, you do not write full sentences. You write 우유 사기 (buying milk). Second, it is perfect for talking about hobbies. If someone asks what you do for fun, you can say 요리하기 (cooking) or 노래 부르기 (singing). Third, it is used in many fixed expressions. For example, ~기 전에 (before doing) or ~기 때문에 (because of doing). Finally, it is used for abstract concepts. When you want to talk about the "difficulty" of a task, you take 어렵다 and make it 어렵기. It turns a feeling into a measurable thing. Imagine you are at a job interview. You might talk about your 계획하기 (planning) skills. It sounds professional and organized.

While -기 is versatile, it is not a total replacement for other noun forms. You should not use -기 as the subject of a long, descriptive sentence. For example, if you want to say "The fact that I went to the store is true," -기 feels too short and clipped. It is also not great for ending a polite conversation with a stranger. Ending a sentence in -기 (like 밥 먹기) sounds like you are talking to yourself or writing a memo. It can come across as cold or robotic if used in the wrong social context. Think of it like a sticky note. It is great for quick info, but you would not write a love letter on one. Also, avoid using it when a natural noun already exists. Why use 공부하기 when you can just say 공부? Keep it simple.

One common trip-up is forgetting the object marker. If you say 책 읽기 좋아해요, it is understandable, but 책 읽기를 좋아해요 is much more natural. Another mistake is over-nominalizing. Beginners sometimes try to turn every verb into a -기 form just because they can. This makes your Korean sound like a technical manual. Also, be careful with the past tense. You cannot really attach -기 to a past tense stem in most casual contexts. You would not say 갔기. Stick to the present stem for general nouns. Native speakers also sometimes mix up -기 and -는 것. If you use -기 when you should use -는 것, you might sound like you are reading a list out loud. Yes, even native speakers mess this up sometimes when they are tired, so don't sweat it too much!

People often ask: "What is the difference between -기 and -는 것?" This is the classic B1 struggle. Think of -기 as an "Abstract Label." It is for titles, lists, and fixed grammar points. It is like the title of a chapter. -는 것 is more like the "Act of Doing." It is much more flexible for creating complex sentences. If you want to say "I like eating," both 먹기 and 먹는 것 work. However, 먹는 것 feels more like you are describing the actual experience of eating. 먹기 feels more like "The activity of eating" as a category. Another one is -음/ㅁ. This is even more formal than -기. You will see -음 in legal documents or very formal reports. If -기 is a sticky note, -음 is a stone tablet.