The word 'sissed' is generally considered a slang term that means scared, timid, or cowardly. Some antonyms or opposites for the word are brave, bold, fearless, gallant, heroic, and intrepid. Other antonyms for 'sissed' may include adventurous, audacious, confident, courageous, daring, dauntless, and resolute. These words indicate strength, courage, and determination, and can be used to describe individuals who are not afraid to take risks, face obstacles, and stand up for themselves and others. Using antonyms is a great way to increase vocabulary and improve communication skills.