back-formation

noun

1. 1

   The process by which a new word is formed from an older word by interpreting the former as a derivative of the latter, often by removing a morpheme (real or perceived) from the older word, such as the verb burgle, formed by removing -ar (perceived as an agent-noun suffix) from burglar.

2. 2

   A word created in this way.

   “Back-formations, such as "tambour" (for "play the tambourine"), are a staple of comedic wordplay.”