The word "prude" refers to a person who is very concerned about being proper, especially regarding matters of sexuality and moral behavior. A prude tends to avoid anything that they consider inappropriate, indecent, or sexually explicit. This can sometimes come across as being excessively modest or easily shocked by topics that are generally accepted in society.
The term "prude" comes from the French word "prude," which means modest or virtuous. It has its roots in the Latin word "prode," meaning "useful" or "virtuous." The word evolved over time to take on the connotation of someone who is overly concerned with propriety.