A functional shift is a shift in the use of a word from one grammatical function to another, such as when a noun becomes a verb. This process is nothing new. In fact, Shakespeare used the functional shift quite often in his plays, which is one of the many reasons why so many of his sayings and phrases are still widely used.
While some grammarians can’t abide the verbing of nouns and adjectives, an even greater number of English users believe it is one of the best things about English, that we can use words so flexibly to express ourselves and be easily understood. It often also allows us to use fewer words, which is perfect for Twitter!
Here are some examples of nouns that also serve as verbs.
the journey—to journey
the tower—to tower over
the father—to father
the commute—to commute
the source—to source
the cushion—to cushion
the drink—to drink
Some adjectives have also made the shift.
single—to single out
smooth—to smooth out
clean—to clean up
narrow—to narrow down
However, the functional shift is not exclusive to nouns, verbs and adjectives. The word like has also undergone a shift, being widely used outside its original prepositional duties, becoming quickly embraced as a conjunction. If you open a dictionary (if you still have one lying around your house somewhere gathering dust), I guarantee you will see at least one word per page that has multiple grammatical uses. English has always been this way and I hope it remains so.
But before you start grabbing any and every noun you can and thrusting them into action, take note that overusing the functional shift can often make your sentences sound clunky. Just remember—the functional shift came into being to make expressing ourselves easier not harder!