Piggybacking is a term which states that something that is riding on the back of something else to complete his/her motive, just like similar to an idiom putting gun to another's shoulder and performing the Hunting, so piggybacking is a term used to refer to access of a wireless internet connection by bringing one's own computer within the range of another's wireless connection, and using that service without the subscriber's explicit permission or knowledge. It is a legally and ethically controversial practice, with laws that vary in jurisdictions around the world. Piggybacking is an unauthorized tapping into another's connection with a public utility.

For e.g.- So piggybacking can be takes place like when I am accessing the wireless connection of my neighbor Wi-Fi without his/her knowledge by hacking his static ip address, then it would be possible for me to access the Wi-Fi connection of others.