Turbid and turgid (which means "swollen or distended" or "overblown, pompous, or bombastic") are frequently mistaken for one another, and it's no wonder. Not only do the two words differ by only a letter, they are often used in contexts where either word could fit. For example, a flooded stream can be simultaneously cloudy and swollen, and badly written prose might be both unclear and grandiloquent. Nevertheless, the distinction between these two words, however fine, is an important one for conveying exact shades of meaning, so it's a good idea to keep them straight. Turbid, like its relative turbulent, comes ultimately from the Latin noun turba, meaning "confusion" or "crowd."