sunny

Compared meaning: full of light or lit up (adjective).

比较义项：明亮、被光照亮（形容词）。

• bright

  The general, everyday word for strong light; can describe a light source, a color, a room, or even weather, without saying where the light comes from.

  最通用的日常词，表示光线强，可以形容光源、颜色、房间甚至天气，并不说明光的来源。

  The bright morning sun woke her up earlier than usual.

  明亮的晨光比平时更早地把她唤醒了。

• sunny 本词

  Describes weather or a place filled with sunshine specifically; not used for artificial light or for the sun itself, only for days, places or moods lit by the sun.

  专门形容天气或地方充满阳光，不用于人工光源，也不直接形容太阳本身，只用于被阳光照耀的日子、地方或心情。

  It was a sunny afternoon, perfect for a walk in the park.

  那是一个阳光明媚的下午，非常适合在公园散步。

• illuminated

  Formal word for something lit up by a light source, usually artificial and often named with 'by'; used for buildings, rooms or objects, not for the sun or for weather.

  较正式的词，表示某物被光源（通常是人工光源）照亮，常与“by”连用，用于建筑、房间或物体，不用于太阳或天气本身。

  The old library was illuminated by soft lamps in every corner.

  那座古老的图书馆的每个角落都被柔和的灯光照亮。

Bright, sunny, and illuminated all relate to light, but differ. Bright is the general word for light, color, or weather. Sunny means full of sunshine, for weather or a place. Illuminated is formal, meaning lit up by a light source. Other senses are not compared.

这三个词都可表示“有光”，但侧重不同：bright 是最通用的说法，可以形容光源、颜色或天气本身很亮；sunny 专指阳光普照的天气或时段；illuminated 则强调某物被（通常是人工的）光源从外部照亮，常用被动结构，语气较正式。这里不比较 bright 表示“聪明的”、sunny 表示“性格开朗的”以及 illuminated 表示“用彩饰装饰的”等其他义项。

Compared meaning: happy, positive, and cheerful in mood (adjective).

比较义项：乐观开朗、心情愉快的（形容词）。

• sunny 本词

  Describes a naturally optimistic, warm disposition, as if radiating warmth like sunshine; usually describes a person's overall character rather than a passing mood, and often pairs with words like nature, disposition or personality.

  形容天生乐观、温暖的性格，仿佛像阳光一样散发温暖；通常形容人整体的性格气质，而非一时的情绪，常与nature、disposition、personality等词搭配。

  Despite the setbacks, he has always had a sunny disposition that cheers everyone around him.

  尽管遭遇挫折，他一直保持着乐观开朗的性格，让身边的人都感到振奋。

• cheerful

  The most common, neutral word for feeling or appearing happy and positive; it can describe a person's mood, a smile, a place or an object, and fits both a momentary state and a lasting trait.

  是最常见、最中性的词，用来形容感到或表现出快乐、积极的状态；既能形容人的情绪、微笑，也能形容地方或物品，既可以表示一时的心情，也可以表示持久的性格。

  The classroom felt cheerful, with colorful posters and children's laughter filling the room.

  教室里洋溢着欢快的气氛，色彩缤纷的海报和孩子们的笑声充满其中。

• cheery

  Suggests a bright, brisk, lively kind of happiness, often shown in short interactions such as a greeting or a tone of voice; slightly more casual and informal than cheerful.

  表示一种明快、轻快、活泼的愉悦感，常出现在简短的互动中，例如打招呼或说话的语气；语气比cheerful更随意、更口语化。

  He answered the phone with a cheery “good morning!” that started my day off well.

  他接电话时用轻快愉悦的语气说了声“早上好”，让我一整天的心情都好了起来。

Sunny, cheerful, and cheery can all describe a happy person, but differ. Sunny suggests a warm, optimistic character. Cheerful is the most common, neutral word, for a mood, smile, or place. Cheery suggests bright, lively happiness, often in greetings. Sunny's weather sense is not compared.

这三个词都可以形容人乐观开朗、心情愉快，但语气和搭配不同：sunny强调天生乐观、温暖的性格；cheerful是最常用、最中性的词，可以形容情绪、微笑或氛围；cheery则强调活泼轻快的愉悦感，常见于打招呼或说话语气中。这里不比较sunny表示“阳光充足的”（天气）的义项。