1. the quality or state of being playfully troublesome or causing minor annoyance in a lighthearted way
Usage: often used to describe playful or teasing behavior, especially in children
2. the quality of being harmful, damaging, or causing trouble or injury
Usage: more serious sense; refers to actual harm or mischief

Examples

• The child's mischievousness was evident in the grin on her face as she hid her brother's shoes.
• His mischievousness got him into trouble at school more than once.
• There was a spark of mischievousness in her eyes when she suggested the prank.
• The puppy's mischievousness included chewing on furniture and stealing socks.
• Her mischievousness masked a deeper kindness and genuine care for others.
• The mischievousness of the prank caused real damage to the school property.