Exhilaration is the feeling itself — that surge of happiness, excitement and energy that comes over you after something thrilling. It is an uncountable noun, so you talk about "a sense of exhilaration," "a feeling of exhilaration," "pure exhilaration," and you do not say "an exhilaration" or "two exhilarations." Writers use it more than speakers do; in conversation people say "it was exhilarating" or "I felt so alive," while a book or an article will say "she felt a rush of exhilaration." That word "rush" is a big clue to its nature: exhilaration arrives quickly and does not stay long. It is also frequently placed next to its opposites, because strong experiences carry both at once — "a mixture of fear and exhilaration" is one of the most common ways the word appears in English.