refactor

Short definition from Wiktionary

Verb

1. 1
   To rewrite existing source code in order to improve its readability, reusability or structure without affecting its meaning or behaviour.
2. 2
   To rewrite existing text in order to improve its readability, reusability or structure without intentionally affecting its meaning. Similar to, but sometimes involving more extensive restructuring than, copy editing.

Noun

1. 1
   The process by which source code is refactored.