texture, skin, body, grain
肌 centers on the surface quality of a body: skin, texture, and grain. The body sense is a natural extension of the skin that covers it.
肌 combines ⺼ (flesh/body part) with 几, which likely contributes the sound. The character expresses the skin or surface of the body.
The flesh radical ⺼ beside 几 looks like a body part with a textured surface. Picture running your hand over skin and feeling its grain.
For キ, imagine a key scratching the skin's surface: key -> キ, and the scratch reveals the texture.
skin
beautiful skin
goosebumps; gooseflesh; goose pimples
bad skin; rough skin; unhealthy skin; skin irritation; skin breakouts
flesh colour (of a Japanese person); flesh color; pale orange
chilly; unpleasantly cold
bare skin; naked skin
the skin (of a human being)
body
underwear; underclothes; lingerie; chemise; singlet
feel; touch; texture
texture; grain
soft fair skin
white-coloured skin
bare rock; rock surface; rock face
mountain's surface; bare surface of a mountain
snow's surface
soft skin; smooth skin
both bare shoulders; stripped to the waist
to strip to one's waist