Questions about amateur status.
In most situations including the rules of most sports, an "amateur" is a participant in a sport who does not receive money or other compensation for that participation. The opposing term is a "professional", someone who is paid to participate in the activity.
In most competitions and other activities in which amateurs are encouraged to participate, professionals are either segregated into a different class of competition, or excluded entirely. The basic idea is that a professional is paid to be good at their sport or other skill, and will therefore have (and take) more time to be good at what they do. An amateur will typically make their living in some other way, and spend the majority of their time and effort on their "day job", therefore putting a professional and an amateur into the same competition, even with a handicap in favor of the amateur, creates an unlevel playing field that discourages amateur participation.
Many sports rigorously define the rules by which a player is entitled to call themselves an amateur, specifically things they cannot do or say while an amateur and expect to remain one. Golf is a common example of such a sport. A golfer is an amateur from the time they begin playing the sport until such time as they accept a cash or material prize with a value exceeding a specific dollar figure, or are ever paid to play or teach the game in a quid-pro-quo manner, or if they have ever explicitly renounced their amateur status. Once amateur status is lost, it typically cannot be regained, though there are some exceptions.
Similar rules exist for other sports which have a notable amateur participation rate, including sports teams and leagues established by U.S. educational institutions, which are designed to be "amateur" leagues by their definition; players in interscholastic leagues including those governed by the NCAA cannot receive compensation for playing beyond tuition, fees, room, board, academic supplies, and certain other direct expenses related to athletic events in which they participate (such as travel).
Notable violations of collegiate compensation restrictions included Southern Methodist University's famous pay-for-play football scandal, in which a "slush fund" contributed to by notable members of the booster club was used to pay illegal compensation to maintain a competitive team. This resulted in the Dallas-based university receiving the NCAA's "death penalty"; on top of a long string of pre-existing probationary penalties including being banned from live TV coverage and participating in bowl games, the SMU Mustangs' entire 1987 season and all four 1988 home games were cancelled (the 'Stangs would eventually cancel their 1988 season entirely as the school was unable to field enough players), with the teams they would have played winning by default. In addition, SMU lost the ability to offer 55 football scholarships for the next four years, and was banned from recruiting off-campus for two years, effectively preventing any notable talent from applying to or remaining with the program. The decision was a major contributing factor to the collapse of the Southwest Conference in one of the biggest shakeups in college athletics history.