A kenning is an expression that replaces a noun or the name of a person that has metaphorical meaning. Usually, the kenning is more than one word, and it is usually hyphenated-as it is an adjective for the person or thing that is replaced.
Ankle-biter = young child
Bookword = someone who likes to read
Four-eyes = someone who wears glasses
Tree huger = someone who cares for the environment
Motor mouth = someone who talks a lot
Head-turner = a pretty or handsome person
Bean counter = accountant
Examples of Kenning in Literature
But the warrior found
the light-of-battle was loath to bite,
to harm the heart: its hard edge failed
the noble at need, yet had known of old
strife hand to hand, and had helmets cloven,
doomed men's fighting-gear. First time, this,
for the gleaming blade that its glory fell.
Light-of-battle = sword
Fighting-gear = armor
From "The Seafarer" by Ezra Pound
Over the whale's acre, would wander wide
Eager and ready, the crying lone-flyer,
Whets for the whale-path the heart irresistibly.
Whale's acre and whale-path = ocean
Lone-flyer = the seafarer