And I'm not real sure* that there should be a hyphen in "goof-up" the way I have used it. I intended it as a verb, in which case "goof up" would probably be more correct. "Goof-up" implies that I intended it to be a noun. Merriam-Webster fails to enlighten me on this, but it does show "goof-off" as a noun rather than a verb. [Having thought it over a bit, I think to "goof up" means to blunder. "Goof-up" means either the blunderer or the blunder itself.]   

But I'd better quit goofing off. I've got of writing to do today, and if I don't get it done, it will qualify as a goof-up.

Don Firth

*I know, I know. To be strictly correct, this should be "really sure," but I'm trying to be a bit informal here. . . .

P.S.: I'm reminded of the story about the ant who asked the centipede, "How do you walk with all those legs?" The centipede blinked a few times, then said, "It's easy. I just pick up this leg . . . no, this one, and then I . . . well, no . . . lemme see . . . I start with this one, then I. . . . " At which point, he zigzags all over the sidewalk and tumbles into the gutter.