Rectitudinous comes to us straight from Late Latin rectitudin- (English added the -ous ending), which itself ultimately derived from the Latin word rectus, meaning both "straight" and "right." (There are other rectus descendants in English, including rectitude, of course, and rectilinear,rectangle, and rectify.) When rectitudinous first appeared in print in 1897, it was in the phrase "notoriously and unctuously rectitudinous." Although rectitude often expresses an admirable moral integrity, rectitudinous has always had a less flattering side. It can suggest not only moral uprightness but also a displeasing holier-than-thou attitude.
