What are red words?
90% of the time, speakers of English use just 7,500 words in speech and writing.These words appear in red, and are graded with stars. One-star words are frequent, two-star words are morefrequent, and three-star words are the most frequent.
once in a blue mooninformal
scream blue murderBritish informal
talk a blue streakAmerican informal
until/till you are blue in the faceinformal