rouge
臙 centers on the color rouge, a vivid red cosmetic or pigment. The meaning is specific and does not extend to broader concepts.
臙 combines the flesh component ⺼ with 燕, which likely contributes the sound エン. The character is used for rouge, possibly through phonetic loan or association with a red pigment.
The flesh component ⺼ suggests something applied to the body, and 燕 (swallow) might evoke the swift, vivid red of a swallow's throat or a cosmetic. Picture rouge made from a swallow's vibrant color.
For エン, imagine the rouge as the color of an enchanting red sunset: enchanting -> エン, and the rouge glows like the evening sky.