An affirmative word that goes one step beyond "definitely." Denotes that they will definitely make a mental effort towards the idea or action they have affirmed, with a humorous, uplifting tone.
Person #1: Are yougonna be at the concert tonight?
Person #2: DEFIMENTALLY!!!
Boys who enjoy yaoi (a genre in Japan that contains sexual and/or romantic relations between two men); literally translates to "rotten boy"; corresponding female : fujoshi