Antonyms for the word "sensiblenesses" include impracticality, irrationality, foolishness, illogicality, and absurdity. While sensiblenesses refer to practicality, sound reasoning, and logical thinking, these antonyms depict the opposite. Impracticality is the quality of lacking utility or feasibility. Irrationality describes the inability to think logically and make sound decisions. Foolishness implies a lack of common sense and judgement. Illogicality refers to reasoning that violates the principles of reasoning or common sense. And finally, absurdity is the quality of being ridiculous or illogical. Using these antonyms in opposition to sensiblenesses can help to emphasize the importance of sound judgement and logical thinking in decision making.