For example a water fall with a name of dry falls?
Oxymoron may fit
An oxymoron is a figure of speech that juxtaposes elements that appear to be contradictory, but which contain a concealed point.
But be aware that with names of geographical features there may be a reference to a seasonal feature which makes a term appear oxymoronic. Dry Falls could well be a feature on a temporary or intermittent river.
Consider contronym (also antagonynm) — Rinkworks.com
The word contronym (also antagonym) is used to refer to words that, by some freak of language evolution, are their own antonyms. Both contronym and antagonym are neologisms; however, there is no alternative term that is more established in the English language.
Contronyms are special cases of homographs (two words with the same spelling). Some examples:
consult - ask for advice, give advice
sanction - approve, boycott
seed - add seeds (e.g., "to seed a field"), remove seeds (e.g., "to seed a tomato")
An oxymoron (usual plural oxymorons, less commonly the Greek-style oxymora):
is a figure of speech that juxtaposes elements that appear to be contradictory, but which contain a concealed point.Oxymorons appear in a variety of contexts, including inadvertent errors (such as "ground pilot") and literary oxymorons crafted to reveal a paradox.
- And faith unfaithful kept him falsely true.