To assure someone you will pay (literally or symbolically) them back, but have no actual plans to do so. You can still have a good heart though, so it is ok.
Ed mooches off of many. Ed mooched off of Rick and Katie, but he promised he would pay them back. Ed eventually buys a ukulele, believing his music will lure in some magic. Ed has a good heart. Therefore, he decides to name his new wave band, The Mooch. The acknowledgement of his moochy ways helps him rest in a grey scaling of the true meaning of repayment . The Mooch becomes successul, attracting many heavy jammers. Ed never forgets the origins of his band's title. He even writes a song called Katie In The Mud With Magic. However, Ed never pays Katie back. Is Ed still a moocher?