BLAHSAY means: If broken into two parts, a street term or phrase – pronounced BLAHH – ZAHY meaning to or used for describing one’s act of telling a tale or fictional story. A term used to criticize someone for their bullshit, false or unsubstantiated claims. It was popular in Brooklyn’s corner shops and dice games during the 1980’s. blahsay BLA HZAY. (in Community Dictionary, added by Finn Mccall)