Elephant in the room

An elephant in the room: um problema ou um assunto que ninguém quer discutir (por ser constrangedor ou tabu) embora ele seja óbvio e todo mundo saiba que ele existe

“When I had dinner with my parents, the elephant in the room was the fact that I’m 45 years old and still single.”

“There was an elephant in the room when I spoke with my mother, because she hates my new boyfriend.”(www.idiommeanings.com)