asteism n. an ingeniously polite insult
Example: ‘ignify’ is audibly close to ‘dignify’, but means ‘to ignite’. Tell your boss that you ensured their important email was printed off and thoroughly ignified and they’ll go away happy, not realising he or she has been ingeniously insulted and that you set fire to their message in the toilet while having a crafty fag*.
*By which I intend, of course, the English colloquialism for ‘cigarette’. I’m not suggesting one should indulge in cottaging or behave like George Michael. Unless one wants to.
Other Words of the Day that are useful examples of asteisms: