Sunacchi

"Sunacchi", which is an abbreviation for a phrase translating to "Throw Away Your Name and Wits", is a battle cry that was once part of the old dialect of Kuri in Wano Country. It has also been used in Roronoa Zoro's homeland of Shimotsuki Village in the East Blue.

Overview
As seen in Ashura Doji's interaction with some of his allies 10 years ago, when they were children around 40 to 50 years before the present day, they used the cry of "Sunacchi" as a form of encouragement to partake in a "test of courage", which for them was cliff diving into the ocean. The cry encouraged them to stop thinking and worrying about the danger they may be in and just take action. Ashura's comrades gave that cry once again 10 years before the present, when they set off in an ultimately fatal journey to Onigashima to take down Kaido. It appears to be considered uncouth language used by commoners, as Kikunojo told Kozuki Momonosuke that it was improper for him, as a daimyo's son, to use.

The cry has also been used in Shimotsuki Village in the East Blue, as Roronoa Zoro recounted hearing it from the older men in the village. He never used it, but told Momonosuke about it to energize the latter in his sword training, saying that it would strengthen his heart when his courage falters.

Trivia

 * The Wano Country version of "Sunacchi" is written differently from the East Blue version that Zoro and Momonosuke use; the Wano version is written in kanji with katakana furigana, while the East Blue version is written in hiragana (すなっち).