It describes someone who performs "mental gymnastics" to avoid accountability, justify poor behavior, or twist logic to make themselves look right when they are clearly wrong.

Organizations like the Gymnastic Ass'n Sokol were vital community hubs for immigrants, providing a space for "all-around" development through rhythmic gymnastics and communal exercise. 2. Slang Context: "Mental Gymnastic Ass"

In modern internet slang and social media, the phrase is often part of a longer insult—.