concubine
姞 centers on a woman in a subordinate marital role: a concubine. The meaning is narrow and specific to this historical social position.
姞 combines 女 (woman) with 吉, which likely contributes the sound. The exact historical development is uncertain, but the structure suggests a phono-semantic compound related to a woman's role.
A woman 女 beside 吉 (good luck) — imagine a woman brought into a household for good fortune, serving as a concubine.
For キツ, picture a concubine who is kitschy, wearing overly ornate clothes: kitschy -> キツ, and the woman 女 is dressed in gaudy finery.