Figure of Speech
Catachresis
From Greek katachresis: misuse. Condemned by classical rhetoricians but valorised by Renaissance poets for boldness; Quintilian distinguished good from bad catachresis.
Definition
The strained or unusual application of a word — a mixed metaphor or an extension beyond normal usage.
Example
'To take arms against a sea of troubles.' (Hamlet) — 'arms' and 'sea' create a mixed but powerful image.