Pale, pallid, ashen, ashy, wan, livid mean devoid of natural or healthy color as applied to a complexion or deficient in vividness or intensity of hue as applied to a specific color.
Pale is the least rich of these words in implications and connotations; it merely implies relative nearness to white and deficiency in depth and brilliance of coloring.
Pallid adds to pale the suggestions of deprivation, rather than absence, of color and of an abnormal condition (as weakness or faintness, or intense weariness); thus, one may be naturally pale but a person made pale by illness would usually be called pallid.
Ashen and ashy definitely suggest not only the pale gray color of ashes but often, also, extreme pallor (as of the skin in death). A thing described as ashen or ashy may therefore be said to be deadly or ghastly pale.
Wan suggests the blanching associated with an unhealthy condition or waning vitality; it usually therefore denotes a sickly paleness.
Livid basically means leaden-hued; it is chiefly used of things, especially of human faces that under the influence of something that distorts them have lost their normal coloring and have assumed a dull grayish tinge.
The word is also applied to various dull or dun colors when the hue is barely apparent.