swell [OE] Swell is a Germanic word brought over by the Anglo-Saxons, appearing as a noun in Middle English, with Shakespeare being the first known user in the sense of rolling waves. As an adjective describing someone stylishly dressed or used as a general expression of approval, it is only early 19th century, but the genesis of this use can be traced back a long way. As early as about 1250 swell could be used to mean behave proudly. By the early 18th century the noun could mean proud behaviour, with cut a swell meaning to swagger, and by the late 18th century it could mean a fashionably dressed person or one of good social position, from which the adjective developed.