I'm trying to find an idiom with knowingly misleading words. For example, consider guinea pig: this animal definitely is not a pig, and its origin is not Guinea. Both words are misleading. In Russian it is called not "guinea pig" but a "sea pig" (if translate the name to English literally), and again: both words are misleading, and that has become some sort of an idiom of giving wrong names to entities. In English however, as an idiom "guinea pig" means somewhat different (a subject to an experiment), so I wish to find an English way to express the nonsense of giving misleading names.
Update: I don't need the name of this term. I have a practical purpose of using an idiom where it is clear to a native speaker that each word it consist of is a misnomer.