"The apparel oft proclaims the man" is a famous line from Shakespeare's Hamlet (Act 1, Scene 3), spoken by Polonius, who gives advice to his son, Laertes, before he travels.
Meaning:
One's clothes reveal one's character, status, and personality to others, essentially "the clothes make the man," advising tasteful, quality dress over flashy, showy attire to project dignity and sense.
It also means people judge your character, status, and competence based on your attire; your clothing signals your personality and influences first impressions, projecting authority or carelessness.
Mark Twain also famously said : "Naked people have little or no influence on society" .
(added by 西岛：Right, naked people are only good for "skinny dipping" 
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- From online with editing
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While reading and laughing with 7G's APAD yesterday, I suddenly remembered the proverb of "the clothes make the man" ("vestis virum facit" in Latin, or 人靠衣装马靠鞍) in one of the books I'm reading (see pic below. Note: Luigi in the fiction book is the Pope).
People often say: Never judge a book by its cover. But in real life, we judge people not only by their looks, but also by their clothing !!! 
Every coin has two sides. This proverb also explains why criminals can fool their victims by hiding under priest's vestments and police uniforms.
Humanity is truly complicated. Sigh ...
Either way, it gives us something to chew for sure.
Have a nice Monday!
