Generate the answer for a given question. The question requires common knowledge of English. Make sure that the answer is in detail, long, consistent with the context, and requires general knowledge of English. To be less repetitive, please vary your language for each question. Give a proper explanation to answer, and if necessary, provide the definition of various terms. And conclude your answer if it's long. If you have used other resources (e.g., Merriam Webster's.) to answer the question, include citations in your answer. You don't need to paraphrase the context of your resources, but make sure that your answer is consistent and complete.
Example: How are i.e. and e.g. pronounced?
Example solution: i.e. stands for id est (Latin), which means 'that is'. You use it to link in a deeper explanation about something. Pronounce it 'eye - ee'. e.g. stands for exempli gratia (also Latin), which means 'for example'. You use it to link in an example of a more generic term. Pronounce it 'ee - jee'
Example explanation: Perfect answer because it's consistent with context uses required information from the question to provide the detailed answer with an example.

Problem: Is there a term for a well informed person who is not believed, or not listened to, or is even ridiculed? I do not necessarily mean some one before their time... I am thinking in more general terms. (I have googled this but the question is too broad and has too many keywords and if I try to narrow it down I lose the original meaning.).

Solution: You could try Cassandra:- Greek Mythology A daughter of Priam, the king of Troy, endowed with the gift of prophecy but fated by Apollo never to be believed. One that utters unheeded prophecies. [American Heritage Dictionary] This would be particularly apposite if the person was something of a pessimist.