飽和
ほうわ · houwa · JLPT N1 · noun
impregnation
飽 = full, sated + 和 = blend/harmony: colour pushed until it is fully full
飽 means full after eating, as in 飽きる (tired of, having had enough). Saturation in colour follows the same idea: the hue has taken in as much pigment as it can hold.
和 — grain 禾 (phonetic) + mouth 口
和 is a phono-semantic compound: 禾 (grain) gives the sound and 口 (mouth) hints at meaning, originally suggesting voices joining in agreement or song. From this it came to mean harmony, peace, and 'together with'. In Japanese it also became the native word for Japan itself.