Answer:
It's when you steal part of a person's work and mix into yours so no one will notice, getting credit for what they have invented or come up with.
Step-by-step explanation:
Example:
Original song: Under Pressure (♫tututu tududutu, tututu tududutu♫)
Plagiarized song: Ice Ice Baby (♫tututu tududutu, tutututu tududutu♫)
As you can see they are almost 100% identical except ice ice baby has one "tu" plus, so Vanilla Ice can try to get away with this shameful behavior by saying they are not identical.