Fraud (or frauding) is a somewhat derogatory term for the practice of getting questions through means other than "real knowledge" of the academic topic being asked. In particular, it is used to describe scenarios in which a player answering has minimal or even no knowledge of the subject.
Common forms of fraud include making one-to-one associations between words and answers without having the slightest idea what the answer really means (e.g., "when I hear 'recoil' I say 'Mossbauer effect'") and memorizing binary-match lists (e.g. eponymous chemical reactions to types of molecules that undergo those reactions). Getting an academic answer through pop culture knowledge is also considered a form of fraud. Questions that encourage or invite fraud are referred to derisively as fraudable, or as transparent.
Because quizbowl is a game and not a rigorous examination, some level of fraud is unavoidable even in events run on the best-written academic questions. Many strong players have selectively used it as part of their strategy; in many cases, the same buzz might be described as "fraud" by one player and as lateral thinking by another.
Subtypes of Fraud
Linguistic fraud (or lingfraud for short) is the practice of getting questions through recognizing the sound patterns of non-English language words and proper names, without having actual knowledge of the meanings of those words or the people/places/things with those names. For example, if a tossup asks for "this country" and names three people with surnames that end in "-ian," a player may draw the inference that, since many surnames from Armenia end in "-ian," the answer must be Armenia. As a check against potential linguistic fraud, writers often omit linguistically-obvious names from the early clues in their tossups.
Style fraud is the practice of getting auditory arts questions by recognizing the musical or other auditory conventions of the genre that the audio comes from, rather than recognizing the particular answer. It is an especial strength of John Lawrence, who popularized the term.
Reverse fraud is a less-commonly used term for the practice of getting a pop culture question through academic knowledge.