The phrase "little terror" may be used to describe a mischievous or unruly child, but there are several synonyms that can be used to convey the same meaning. Some possible alternatives include "imp," "rascal," "mischief-maker," "troublemaker," "hellion," "scamp," "brat," and "tyke." Each of these terms highlights a particular aspect of a child's behavior, with implications ranging from playfulness to defiance. By choosing the right synonym based on the context and tone of the sentence, a writer can add nuance and humor to their description of a troublesome child.