Back-formation

In etymology, back-formation is the process or result of creating a new word via inflection, typically by removing or substituting actual or supposed affixes from a lexical item, in a way that expands the number of lexemes associated with the corresponding root word. The resulting is called a back-formation, a term coined by James Murray in 1889. (Oxford English Dictionary Online preserves its first use of 'back-formation' from 1889 in the definition of to burgle; from burglar.)

For example, the noun resurrection was borrowed from Latin, and the verb resurrect was then back-formed hundreds of years later from it by removing the -ion suffix. This segmentation of resurrection into resurrect + ion was possible because English had examples of Latin words in the form of verb and verb+-ion pairs, such as opine/opinion. These became the pattern for many more such pairs, where a verb derived from a Latin supine stem and a noun ending in ion entered the language together, such as insert/insertion, project/projection, etc.