【Appearance】 , 【look】 , 【aspect】  and semblance denote the outward show presented by a person or thing.

【Appearance】 often carries no additional implications.

• judge not according to the 【appearance】
  —Jn 7:24
• in drawing, represent the appearances of things, never what you know the things to be
  —Ruskin

The word, however, frequently implies an apparent as opposed to an actual or genuine character and therefore often connotes hypocrisy, dissembling, or pretense when used of persons or their actions.

• to be able to tyrannize effectively they needed the title and 【appearance】 of constitutional authority
  —Huxley
• they spent their lives trying to keep up appearances, and to make his salary do more than it could
  —Cat her

【Look】 is often indistinguishable from 【appearance】 except that it more often occurs in the plural.

• never judge a thing merely by its looks

They are not interchangeable, however, in all instances. When a personal impression or a judgment is implied, 【appearance】 is the precise word.

• Aristotle . . . while admitting that Plato′s scheme has a plausible 【appearance】 of philanthropy, maintains that it is inapplicable to the facts of human nature
  —Dickinson

When the emphasis is upon concrete details (as of color, shape, or expression) observable to everybody, 【look】 is a better choice.

• he had the 【look】 of a man who works indoors and takes little exercise
• I choose my friends for their good looks, my acquaintances for their good characters, and my enemies for their good intellects
  —Wilde

Specifically 【look】 is often applied to a person′s expression as manifest in his face or posture.

• she had a 【look】 about her that I wish I could forget—the 【look】 of a scared thing sitting in a net!
  —M May

【Aspect】 , like 【look】 , stresses the features of a person or thing but when applied to persons, it usually distinctively suggests the characteristic or habitual 【appearance】 and expression, especially facial expression.

• not risking a landing because of the fierce 【aspect】 of the natives
  —Heiser
• he was a very handsome man, of a commanding 【aspect】
  —Austen

【Aspect】 often specifically implies reference to a facet or to the features that give something (as a place, an age, or a situation) its peculiar or distinctive character.

• the 【aspect】 of affairs was very alarming
  —Dickens
• fifty years from now, it may be, the olive tree will almost have disappeared from southern France, and Provence will wear another 【aspect】
  —Huxley
• democracy . . . has different aspects in different lands
  —Sulzberger

Semblance basically implies outward seeming without necessarily suggesting a false 【appearance】 .

• it is the semblance which interests the painter, not the actual object
  —Times Lit. Sup.

Nevertheless it is rarely used in this sense without an expressed or implied contrast between the outward 【appearance】 and the inner reality.

• thou, whose exterior semblance doth belie thy soul′s immensity
  —Wordsworth

Sometimes, however, the word stresses the likeness of the thing to something else without suggesting deceptiveness in the 【appearance】 .

• a piked road that even then had begun to take on the semblance of a street
  —Anderson