Charlatan in the context of "Snake oil"

Physiognomy or face reading, sometimes known by the later term anthroposcopy, is the practice of assessing a person's character or personality from their outer appearance—especially the face. The term physiognomy can also refer to the general appearance of a person, object, or terrain without reference to its implied characteristics—as in the physiognomy of an individual plant (see plant life-form) or of a plant community (see vegetation).

Physiognomy as a practice meets the contemporary definition of pseudoscience and is regarded as such by academics because of its unsupported claims; popular belief in the practice of physiognomy is nonetheless still widespread and modern advances in artificial intelligence have sparked renewed interest in the field of study. The practice was well-accepted by ancient Greek philosophers, but fell into disrepute in the 16th century while practised by vagabonds and mountebanks. It revived and was popularised by Johann Kaspar Lavater, before falling from favour in the late 19th century. Physiognomy in the 19th century is particularly noted as a basis for scientific racism. Physiognomy as it is understood today is a subject of renewed scientific interest, especially as it relates to machine learning and facial recognition technology. The main interest for scientists today are the risks, including privacy concerns, of physiognomy in the context of facial recognition algorithms.

A crystal ball is a crystal or glass ball commonly used in fortune-telling. It is generally associated with the performance of clairvoyance and scrying through crystal gazing. Used since Antiquity, crystal balls have had a broad reputation with witchcraft, including modern times with charlatan acts and amusements at circus venues, festivals, etc.

Other names for the object include crystal sphere, orbuculum, scrying ball, shew/show(ing) stone, and more variants by dialect.

Quackery, often synonymous with health fraud, is the promotion of fraudulent or ignorant medical practices. A quack is a "fraudulent or ignorant pretender to medical skill" or "a person who pretends, professionally or publicly, to have skill, knowledge, qualification or credentials they do not possess; a charlatan or snake oil salesman". The term quack is a clipped form of the archaic term quacksalver, derived from Dutch: kwakzalver a "hawker of salve" or rather somebody who boasted about their salves, more commonly known as ointments. In the Middle Ages the term quack meant "shouting". The quacksalvers sold their wares at markets by shouting to gain attention.

Common elements of general quackery include questionable diagnoses using questionable diagnostic tests, as well as untested or refuted treatments, especially for serious diseases such as cancer. Quackery is often described as "health fraud" with the salient characteristic of aggressive promotion.

Psychic surgery is a medical fraud in which practitioners create the illusion of performing surgery with their bare hands and use sleight of hand, fake blood, and animal parts to convince the patient that diseased lesions have been removed and that the incision has spontaneously healed. The technique may fool the general public, but it can be observed by experienced stage magicians, who use the same sleight of hand techniques for entertainment.

The US Federal Trade Commission described psychic surgery as a "total hoax". It has also been described as fraud, fakery, deceitful, irrational, charlatanry, and quackery. Even supporters have been forced to admit that sleight-of-hand tricks were "widely used" and that charlatans were common and miracles unlikely. Psychic surgery may cause needless death by keeping the ill away from life-saving medical care. Medical professionals and skeptics classify it as sleight of hand and any positive results as a placebo effect.

Georg Joseph Vogler, also known as Abbé Vogler (15 June 1749 – 6 May 1814), was a German composer, organist, teacher and theorist. In a long and colorful career extending over many more nations and decades than was usual at the time, Vogler established himself as a foremost experimenter in baroque and early classic music. His greatest successes came as performer and designer for the organ at various courts and cities around Europe, as well as a teacher, attracting highly successful and devoted pupils such as Carl Maria von Weber. His career as a music theorist and composer however was mixed, with contemporaries such as Mozart believing Vogler to have been a charlatan. Despite his mixed reception in his own life, his highly original contributions in many areas of music (particularly musicology and organ theory) and influence on his pupils endured, and combined with his eccentric and adventurous career, prompted one historian to summarize Vogler as "one of the most bizarre characters in the history of music".