Invalidities refer to the condition of being invalid or lacking validity. Antonyms for the word "invalidities" can be validity, soundness, or credibility. These words convey the idea of something being valid, reliable, and truthful. Validity refers to the quality of being true or accurate, and soundness connotes the idea of something being healthy and complete. Credibility, on the other hand, pertains to the quality of being trusted and believed in. These antonyms serve to highlight the importance of having valid and reliable information, opinions, and arguments that are based on sound evidence and reasoning.