Taylor Swift: Suers Gonna Sue, Sue, Sue ... She Jacked My Song!

Taylor Swift can "Shake It Off" all she wants, but if she sings about haters hating ... then she's gonna have to pay the songwriter who first came up with the phrase ... according to a new lawsuit.

Jessie Braham says Taylor's signature hit borrows heavily from a song he wrote in 2013 called "Haters Gone Hate." Braham says his lyrics are "Haters gone hater, playas gone play. Watch out for them fakers, they'll fake you everyday."

He points out that his song phrase is used more than 70 times in Taylor's 2014 song. He's basically saying ... her entire chorus is a ripoff of his song.

Braham, who goes by Jessie Graham on his track ... wants $42 million from Taylor, and wants his name added to any new prints of "Shake It Off."

Apparently he hasn't heard most people download or stream music now. Anyway, checkout his song compared to Taylor's.