Rihanna's Fenty Universe Being Called a Rip Off By Another Brand

Rihanna's "Fenty University" accused of jackin' its initials from another clothing brand.

RiRi's Fenty label through Puma is being targeted by Freedom United, an American fashion brand that happens to use the initials FU on its gear ... which it boasts has been worn by celebs like Demi Lovato.

Freedom sent Puma a cease and desist letter in January, spelling out how Rihanna had knowledge of its FU mark for at least a couple of years, yet still chose to use 'F.U.' for her line of Fenty University products.

The company asked Puma to stop making the 'F.U.' gear and to release a full accounting of how much cash RiRi made from her 'F.U.' line.

Puma responded back in March with its own letter insisting there was no infringement on Freedom's 'FU' because Rihanna's 'F.U.' used a completely different font. Besides, Puma claims, FU is not a unique trademark ... it's just initials. Puma also says the Fenty U merch ran its course and is no longer being produced.

Freedom United plans to file a lawsuit against Puma soon.