Why 춥다 Becomes 추워요, Not 춥어요: The ㅂ Rule Behind Hot, Cold, and Spicy

Back when you learned present tense, the rule was clean: chop off 다, add -아요 or -어요. 먹다 → 먹어요. 가다 → 가요. Then you tried to say “it’s spicy” — 맵다 — and a Korean said 매워요, not 맵어요. Where did that 워 come from?

Here’s the answer, and it unlocks a whole set of the most useful words in the language: weather, taste, and difficulty. When a ㅂ sits at the bottom of the stem, it doesn’t just take an ending — it melts into 워.

The whole rule, up front

Take the dictionary form (the ~다 word), drop 다, and look at the bottom of what’s left. If it ends in ㅂ, you don’t add -어요 the normal way. Instead:

Drop the ㅂ, and add 워요.

• 춥다 (cold) → 추 + 워요 → 추워요🔊 (it’s cold)
• 덥다 (hot) → 더 + 워요 → 더워요🔊 (it’s hot)
• 맵다 (spicy) → 매 + 워요 → 매워요🔊 (it’s spicy)

That’s it. The ㅂ leaves, 워요 arrives. ==When a stem ends in ㅂ, drop the ㅂ and add 워요.==

💡 You might see it explained as “ㅂ → 우, then + 어요” (추 + 우 + 어요 → 추워요). Same result — the 우 and 어 fuse into 워. Just remember the finished shape: 워요.

Why this matters: it’s the “how does it feel?” rule

Look at what kind of words these are. They’re the ones you reach for constantly — describing the weather, food, and how hard something is:

💡 Words · 춥다 → (be) cold · 덥다 → (be) hot · 맵다 → (be) spicy · 쉽다 → (be) easy · 어렵다 → (be) difficult

Notice the vowel of the stem never matters — 춥 has ㅜ, 맵 has ㅐ, but they both end in 워요. Unlike the regular -아요/-어요 split, here there’s no bright/dark decision to make. ㅂ always becomes 워. One shape, every time.

Hear the switch

Say the dictionary form, then the ㅂ-irregular. Listen for the ㅂ disappearing and 워 taking its place:

맵다🔊 → 매워요🔊 (spicy → it’s spicy)

맵다: the dictionary form ends in ㅂ. Drop 다, and you’d expect 맵어요 — but the ㅂ doesn’t survive. It melts into 워: 매워요. Say it a few times and your ear will stop expecting the ㅂ.

In the past: the same 워, with a ㅆ

You already know the past tense (drop 요, add a ㅆ on the bottom, then 어요). It works here too — you just start from the 워 form:

더워요 → drop 요 → 더워 → put a ㅆ on the bottom → 더웠 → add 어요 → 더웠어요. The 워 stays; the past tense lands on top of it, exactly like every other verb you’ve met.

💡 So yesterday’s weather is 어제 더웠어요 (it was hot yesterday) or 어제 추웠어요 (it was cold yesterday).

Where it shows up

Half of small talk in Korea is about the weather and food. Watch how naturally these come up:

💡 Words · 오늘 — today · 날씨 — weather · 어때요? — how is it? · 너무 — too (much) · 이거 — this · 조금 — a little

The honest catch: some ㅂ words are regular

Here’s the part textbooks gloss over, and it’s better you hear it straight. Not every word ending in ㅂ is irregular. A few common ones follow the normal -아요/-어요 rule:

• 입다 (wear) → 입어요🔊 — regular, not 이워요
• 좁다 (be narrow) → 좁아요🔊 — regular, not 조워요

Look at 좁다 (narrow) and 춥다 (cold): they end the same way, look identical — yet 좁다 is regular (좁아요) and 춥다 is irregular (추워요). There’s no clue in the spelling. Whether a ㅂ word is irregular is a fact you learn with the word, not a rule you can predict.

The good news: the describing words you’ll use most — the weather-taste-difficulty set above — are all irregular (추워요, 더워요, 매워요…). Learn those as a group, and you’ve got the ones that come up every single day. The handful of regular ㅂ words (입다, 좁다) you’ll pick up one at a time.

💡 It’s about the word, not whether it’s an action or a description — most of these happen to be describing words, but 굽다 (grill) is an action verb and it’s still irregular (구워요). Learn the ㅂ words one by one and you’ll know which is which.

💡 One common verb bends even further — 돕다 (help) → 도와요 takes 와, not 워. You don’t need it yet; just don’t be surprised to find 도워요 marked wrong.

Now say your own

Turn each dictionary form into its polite -요 form. Say it out loud before opening the answer.

1. 춥다 (be cold) — the classic ㅂ word.

answer

추워요🔊 — drop the ㅂ, add 워요 → 추워요. (it’s cold) The ㅜ in 춥 doesn’t matter — ㅂ always goes to 워.

2. 쉽다 (be easy) →?

answer

쉬워요🔊 — drop the ㅂ, add 워요 → 쉬워요. (it’s easy) So “Korean is easy” = 한국어는 쉬워요.

3. 덥다 (be hot) — now put it in the past: “it was hot.”

answer

더웠어요🔊 — first the 워 form (더워요), then the past: drop 요, ㅆ on the bottom, add 어요 → 더웠어요. (it was hot)

Quick check

Q1 — make the 워 form. 맵다 (spicy) becomes:

why

The ㅂ melts into 워 → 매워요. 맵어요 is the trap: it keeps the ㅂ, which the irregular never does.

Q2 — regular or irregular? You want to say “I wear” from 입다. Which is right?

why

입다 is regular → 입어요 (the ㅂ stays). It looks just like 춥다, but it doesn’t follow the irregular rule — that’s the honest catch. You learn it word by word.

Q3 — from last time. Back in past tense, how did you turn 추워요 into “it was cold”?

answer

추웠어요🔊 — drop 요 → 추워 → ㅆ on the bottom → 추웠 → add 어요 → 추웠어요. (it was cold) The 워 stays put; the past tense just stacks on top.

Before you go

• When a stem ends in ㅂ, drop the ㅂ and add 워요 (춥다 → 추워요) — the stem’s own vowel never matters
• The everyday weather / taste / difficulty words are all irregular: 추워요 · 더워요 · 매워요 · 쉬워요 · 어려워요
• Past tense sits right on top: 더워요 → 더웠어요 (it was hot)
• The honest catch: a few ㅂ words are regular (입다 → 입어요, 좁다 → 좁아요) — you learn which is which with the word, not from a rule

📌 Pocket cheat sheet: ㅂ at the bottom → drop it → add 워요. 추워요 · 더워요 · 매워요 · 쉬워요 · 어려워요.

You can now describe how things feel — hot, cold, spicy, easy, hard — the words that carry half of everyday small talk. Next up, two more irregular patterns hiding in words you use every day: 모르다 (to not know) and 듣다 (to listen). Same idea, different bend.