[{"Bold_text": "noun", "List Items": ["Slang.an eccentric or irrational person; a nut :When the FBI first looked into him, they thought he was a harmless screwball.", "Baseball.a pitched ball curves toward the side of the plate from which it was thrown, in a trajectory opposite to that of a curve ball:Has the once popular screwball vanished completely from the major leagues?"]}, {"Bold_text": "adjective", "List Items": ["Slang.eccentric or irrational; nutty :What a screwball idea!"]}]