Definition
Obfuscation runs when you build the game, not while anyone is playing. Renaming replaces class, method, and field names with names that carry no meaning. Control-flow obfuscation rearranges the path through a method so a decompiler is harder to follow. Other passes hide strings such as URLs. The game still behaves the same. The shipped build is harder to read and harder to patch.
Relevance
An unprotected Unity build shows code, strings, and logic quickly. Build-time obfuscation slows that first look and makes small edits less reliable, which protects launch windows and secrets that have to live in the client. It does not watch the running game. An anti-cheat does that.
Example
A method named ApplyDamage is easy to find and change in a decompiler. After renaming and control-flow obfuscation, that method has a meaningless name and a path that is hard to follow, so changing the damage logic takes much longer.
Connected
Synonyms
Code obfuscation, Assembly obfuscation