Coming from the latin words "casus" (adventure) and "motus" (excitement) - The feeling of simultaneous excitement and trepidation that arises when you're about to embark on a thrilling adventure or take a leap into the unknown, not knowing what the outcome will be.
Standing at the edge of the unknown jungle, the brave adventurer felt a mix of excitement and nervousness, a sensation of motacasus growing with each step deeper into the mysterious forest, their heart raced with anticipation and fear. They were about to start a thrilling adventure, full of surprises and challenges, and the feeling of motacasus would soon prove a constant companion on their journey.