The word "笑嘻嘻" is formed by starting with the character 笑, which means "to laugh" or "smile", and then adding two repetitions of the character 嘻, which is an onomatopoeic element imitating the sound of laughter or giggling. This combination creates a trisyllabic descriptive term that conveys a state of laughing or smiling in a cheerful, audible manner.