muddying the waters

Verb

muddy the waters (third-person singular simple present muddies the waters, present participle muddying the waters, simple past and past participle muddied the waters)

1. (idiomatic, informal) To make something unclear and difficult to understand.
   • He insisted that the Basque separatist group Eta remained the main line of investigation, and suggested the tape may have been an attempt to muddy the waters.2004 March 12, Giles Tremlett, “The clues that point towards al-Qaida”, in The Guardian, →ISSN