Commonly used by gumshoes in books by Chandler and Spillane. If something is as good as done or will be done very easily is said to be "duck soup."
It's duck soup from here on out.
A common phrase in baseball, elephant ears are simply when the pockets of a player's pants are seen outside of their slits (which happens often to back pockets which are in no way attached to the inside of the pants). Phrase made most popular by Duane Kuiper and Mike Krukow, San Francisco Giants TV broadcasters.
After sliding into second, Barry Bonds developed two elephant ears.
Raymond Chandler simply defines a Loogan as, "A guy with a gun."
Phillip Marlowe is always on the lookout for any Loogan dumb enough to draw a gat on him.