Functional shift refers to a change in the grammatical function of a word， as in the use of the noun input as a verb or the noun fun as an adjective. Words may shift from one part of speech to another without the addition of affixes. Conversion is also known as functional shift. In linguistics, functional shift occurs when an existing word takes on a new syntactic function. For example, the word “like”, formerly only used as a preposition in comparisons (as in “eats like a pig”)， is now also used in the same way as the subordinating conjunction as in many dialects of English (as in “sounds like he means it”).