One who is average at everything and does not exhibit qualities of one extreme in regards to any endeavor. Derived from lets split a ten sack, or spend half of ten.
Eric is not fat, but hes not skinny, therefore he's a halften. He's not boring, but hes certainly not fun, so he's a halften. He doesn't love bars, but he definitely doesnt hate bars, he's a halften. He's not a good athlete, but hes not a bad athlete, hes more like a halften. He's not ugly, but hes not George Clooney so hes a halften