scandalously repackaging and claiming to have purchased on your own a previously received hideous piece of crapola and giving it to someone else as if you had actually been thinking about what they would enjoy.
Your mother buys you some crappy made in china plastic wal mart creation. You unwrap it, take off any identifying tags, place it in a box from Saks fifth avenue, and "regift" it to someone else.
regifting is when you receive a rubbish, thoughtless present from someone, so instead of using it, or throwing it away, you save it until next year, wrap it up and give it to the same person who gave it to you.
Me: Mark, a can opener.... Thanks...
Me: Here Mark, here's your Christmas present.
Mark: A can opener? How dare you fucking regift me this!