Answer:
True, Kenning is a double metaphor that is usually hyphenated.
Explanation:
According to the Merriam Webster dictionary, Kenning is defined as a "metaphorical compound word or phrase that is used especially in Old English or Old Norse poetry". So, kenning can be roughly explained as those two-worded words that are metaphorically used to mean something else. Some examples of kenning are-
bookworm - someone who reads a lot,
four eyes - someone who wears glasses
fender bender- a car accident
first lady - the wife of the president etc. etc.
