高级词汇是指那些词汇量比较大，难度较高的单词或短语。这些词汇通常用于专业性领域或学术场合。来源可能包括学习和阅读专业书籍和文章，以及与专家交流。

例如:

"Propferation" (noun) 意思是扩散,增殖.例句: The propferation of cell phones has changed the way we communicate.
"Plethora" (noun) 意思是过量,大量. 例句: There is a plethora of options available for people looking to buy a new car.
"Conundrum" (noun) 意思是迷惑,疑难. 例句: The conundrum of cpmate change is one of the most pressing issues facing the world today.