In my art world the three characteristics of any color are hue (where it falls on the color wheel, or what it's closest to), value (how light or dark it is), and intensity (how intense the color is; dull/muted or intense\bright or somewhere in between?)
Your words are a bit different, but you are talking about the same factors.
The colors on the color wheel are as intense as they get. Anything less intense goes either lighter or darker.
Lessening the intensity of color-wheel yellow, since it's the lightest color on the color wheel, has to make the new color darker than the original one. Unless you simply add white to it, in which instance it gets lighter.
Lessening the intensity of color-wheel purple, since it's already so dark, usually lightens its value.
I used to teach my art students that the shadow version of color-wheel yellow dark (which is a lower value of yellow) is paper bag/khaki. This is not obvious.
And that color-wheel orange, when in shadow, looks like some version of Hershey's chocolate brown. This also is not obvious.
In real life, the loss of intensity of an intensely colored object can come from loss of light shining on something, aka a shadow, or it can come from a weakened version of the color such as fading. Or from dirt getting on the surface of the colored object. These are usually called tints and shades when we mix them manually using paint.
Why are we talking about this??? TLDR.