Short definition: a “repack” is a redistributed packaged version of software (commonly games) modified to reduce size, remove DRM, or bundle fixes—sometimes illegally. “Gnarly repacks” are those that caused major user harm: malware, rollback of features, corrupted saves, or legal trouble.
Before we wade into the infamous and gnarly, we need a baseline. In piracy and software sharing circles, a repack is a modified version of an existing cracked software or game. infamous gnarly repacks
The primary reason infamous repacks are viewed with such skepticism is the concept of "cherry picking." Short definition: a “repack” is a redistributed packaged