also: けらけらわらう
godan verb (-u), intransitive verb
cackle; laugh shrilly
Describes a high-pitched, often childish or silly laugh, sometimes with a connotation of being carefree or slightly annoying.
子供たちはケラケラ笑いながら遊んでいる。
The children are playing while cackling with laughter.
彼女は何がおかしいのか、一人でケラケラ笑って
She was cackling to herself, as if something was funny.