Just this afternoon, my brother and I were talking about "big words" and the people who use them. These "big words" which usually have at least 3 syllables aren't usually used in daily life and often have simpler counterparts.
According to him, it is better to use smaller words, especially in writing. This is so the reader is able to better understand the text.
But the word kerfuffle to me is different from the word fuss: The essence may be the same, but there are differences between the two, as two slices of new york cheesecake from different sources may have different tastes, textures, presentation and price. I myself am fond of the former example because of the light-heartedness the word implies for me (because it sounds close to fluff).
As to NOT knowing the meaning of the word, a dictionary (or dictionary app) can always be used to find its definition. Sometimes, it is not even needed! The use of context clues may help clarify the meaning of the word. In fact, children often learn what words mean without being given the actual definition of a word.
Learning is a wonderful thing.
If you do decide to use big words, you should be very aware of what these words actually mean. There is the chance of embarrassment when pointed out by a more knowledgeable companion.
Also, be prepared to be called a pompous pie hole and the like.