Vain, empty, worthless, only found in Matt. 5:22. The Jews used it as a word of contempt. It is derived from a root meaning “to spit.”

a term of reproach derived from the Chaldee reka, worthless. (“Raca denotes a certain looseness of life and manners, while ’fool,’ in the same passage, means a downright wicked and reprobate person.”) (Matthew 5:22)