Because modern English has shed most of the flexional endings that distinguish grammatical functions, many of our words possess the lively ability to rail-jump from one part of speech to another without any basic change in form. This happy facility, variously called conversion or function shift, endows our vocabulary with vitality, power and a prolific source of new words.
Word Ways: Vol. 48
, Article 13.
Available at: http://digitalcommons.butler.edu/wordways/vol48/iss2/13