暖かい
atatakai
/ɐ.tɐ.tɐ.ˈka.i/
Definition
Warm in temperature or feeling; used to describe pleasant heat from the sun, a room, or a person's kindness.
Example
今日は暖かいから、公園で昼ごはんを食べよう。
Show translation
It's warm today, so let's eat lunch in the park.
Etymology
Derived from the classical Japanese verb 暖まる (atatamaru, "to become warm"). The root atata- is an ancient reduplication expressing a gentle, sustained warmth — as opposed to 熱い (atsui), which means hot enough to burn. The kanji 暖 (from Chinese 暖 nuǎn) carries the sense of mild, comfortable heat.
Cultural note
Japanese distinguishes carefully between 暖かい (atatakai) for ambient, pleasant warmth — weather, rooms, hearts — and 熱い (atsui) for dangerously hot things like boiling water or a fever. Mixing them up is a very common learner error. Additionally, 暖かい is frequently used metaphorically: 暖かい人 (atatakai hito) means a warm-hearted, kind person, just as in English.