colourfast的音標為：[?k?l??fɑ?st] ，中文翻譯為"耐洗的，不褪色的"。

速記技巧：使用詞根詞綴記憶法，其中colour為“顏色”的意思，fast為“快速的”的意思，組合起來可以理解為“顏色不容易褪色”。

Colourfast這個詞的英文詞源可以追溯到拉丁語詞根“color”和“fastus”，意為“堅固的，耐久的”。它的變化形式包括其過去式“colourfast”和過去分詞“colourfast”。

相關單詞：

1. “Colours” - 源自拉丁語詞根“color”，意為顏色。

2. “Fade” - 源自古英語詞根，意為“消失，減弱”，與colourfast相反。

3. “Permanent” - 源自拉丁語詞根“per”和“manere”，意為“持續的，不變的”，與colourfast有相似含義。

4. “Stain” - 源自中世紀英語詞根，意為“污染，污漬”，與colourfast相反。

5. “Fasten” - 源自拉丁語詞根“fastus”和動詞詞尾，意為“固定，綁住”，與colourfast有相似含義。

6. “Unfasten” - 意為“解開，松開”，與“fasten”相反。

7. “Vivid” - 源自拉丁語詞根“vivus”，意為“生動的，鮮明的”，與colourfast表示的顏色鮮明、持久的特點相符。

8. “Durable” - 意為“耐用的，持久的”，與colourfast表示的顏色持久的特點相符。

9. “Fadeless” - 意為“不褪色的”，與colourfast表示的顏色持久的特點相符。

10. “Stale” - 意為“陳舊的，過時的”，與顏色新鮮、持久的特點相反。

以上單詞都與colourfast這個詞有密切關聯，并且描述了顏色在不同方面的特征。

常用短語：

1. colourfast dyes 固色染料

2. colourfastness test 固色牢度測試

3. colourfastness rating 固色等級

4. colourfastness guarantee 固色保證

5. colourfastness after washing 洗后顏色保持

6. colourfastness underwear 耐洗內衣色牢度

7. colourfastness of fabric 面料顏色保持力

雙語句例：

1. The fabric is highly colourfast and will maintain its original hue even after multiple washings. （面料耐洗，顏色保持力強，多次洗滌后仍能保持原色。）

2. The dye used in our clothes is highly colourfast, ensuring that they will not fade even after prolonged exposure to sunlight. （我們衣服所用的染料具有很高的固色牢度，可以確保衣物即使在長時間暴露于陽光下也不會褪色。）

3. The colourfastness of this fabric is excellent, making it suitable for use in high-end clothing brands. （這種面料的顏色保持力非常好，適合用于高端服裝品牌。）

4. We recommend using a mild detergent and avoiding exposure to harsh chemicals to ensure the colourfastness of your clothes. （我們建議使用溫和的洗滌劑，并避免接觸強酸強堿化學品，以確保衣物的顏色保持力。）

5. The colourfastness of this shirt is excellent, making it suitable for both casual and formal occasions. （這件襯衫的顏色保持力非常好，適合休閑和正式場合。）

6. The colourfastness of our socks is guaranteed, ensuring that they will maintain their original hue even after multiple wears. （我們的襪子顏色保持力有保證，可以確保襪子多次洗滌后仍能保持原色。）

7. The use of colourfast dyes ensures that our products will maintain their original hues for a long time. （使用固色染料可以確保我們的產品長時間保持原色。）

英文小作文：

Colourfastness is an important factor in determining the quality of a product, especially when it comes to clothing and textiles. When choosing clothes, we often look for items that will maintain their original hues for a long time, without fading or bleeding color onto other clothes or fabrics nearby. This is especially important for underwear, socks, and other items that are frequently washed and worn. Therefore, it is essential to ensure that the dyes used in the production process are colorfast, which means they will not fade or wash off easily. Using high-quality colorfast dyes ensures that clothing items will maintain their original hues for a long time, making them more durable and more suitable for frequent wear and washing. Additionally, colorfastness testing should be conducted on each batch of fabric to ensure that the dyes used are effective and durable, and that the finished product meets the required standards for colorfastness. Therefore, when choosing clothes, it is essential to look for items that have been produced using high-quality colorfast dyes, ensuring that they will maintain their original hues for a long time and providing maximum wearability and durability.