The term 'insignificant bit' can be broken down into three crossword solutions: FLYSPECK (8 letters), WHIT (4 letters), and sou (3 letters). FLYSPECK is an old-fashioned word meaning a tiny speck, usually referring to dust or dirt. WHIT is an archaic term for the smallest particle imaginable. Sou is an informal word for a very small amount of something. Together, these three words describe something that is so small it is almost insignificant.