CoGrOO stands for "OpenOffice Grammar Checker" (in Portuguese, "Corretor Gramatical para o OpenOffice"), and recently it reached version 1.0. I couldn't find an ebuild for it, and failed in creating one. Related thread in the Portuguese forum: http://forums.gentoo.org/viewtopic-t-462752.html
No progress here for 1 year; closing WONTFIX. Feel free to reopen with an ebuild.