Code Reef
Noun · Slang & Abbreviations
Definitions
A cluster of hard-to-see technical obstacles just below the surface of a system. In engineering slang, a code reef is dangerous because things look navigable until a change scrapes against hidden structure.
In plain English: A hidden cluster of technical obstacles just under the surface.
Example: "The API looked stable from the outside, but every partner customization formed a code reef that shredded naive attempts to simplify the contract."