Whether they're long, fancy, dated, or just really cool sounding, there's a few rules of thumb I find handy to keep your ten-dollar words from working against you. The fanciest word is not always the best word! It is usually better to use the word that quickly gets your meaning across, especially outside of dialogue. If a reader has to pause to consider what the word means - or worse, to look it up - the pacing, tone, and focus of your writing is compromised. it takes less time to envision someone 'walking' than 'perambulating' Thesauruses are awesome for if the first word you think of isn't quite right, but avoid synonym-hopping! You can end up with a word that doesn't even mean what you want anymore if you start looking for words that sound fancy over words that get the point across. Tone The vocabulary you choose will effect the tone and voice of the story and the characters. A character who would say they were feeling 'serendipitous' gives a different impression than one who says they are feeling 'lucky'. People will perceive your characters differently if their dialogue requires a dictionary. This is true of your descriptive voice as the narrator, as well. Nobody likes reading with a dictionary in the other tab Ten-dollar words are, every now and again, the best word for the situation, winning out even over more readily understood synonyms. So if it's really just gotta be 'perambulate' and not 'walk', make sure the context at least lends a hint of what this weird word means. Advancing your vocabulary with big words is cool and fun, but use these words wisely!