The Rice University Neologisms Database

To become or to render attractive. Prettify is similar to beautify in meaning and form. Pretty is probably re-analyzed to form prettify by adding the suffix “-ify” in beautify. However, prettify refers to a different attractiveness than beautify. A group of university students dressing up for a formal ball can be described as pretty, but not beautiful; unless perhaps, the beholder is particularly enamored. The adjective beautiful tends to be applied to a great deal of things, some of which are not grand or profound enough to deserve such distinction. As a result, the meaning of beautiful is somewhat cheapened. Prettify strives to preserve the prestige of Beauty by correctly differentiating those that are truly beautiful, and those that are pretty.