A reference to a woman who is a "10" (on a scale of 1-10) and thus very attractive. It's important to note it's derived from "dimebroad" and then given the suffix "izzle" (or is "izzl-ized") in the tradition of E-40 and Snoop Doggy Dogg.
I came up on a serious dime-brizzle at the spot last night.