This word either means you were drunk, stoned, or both when saying it. The exact meaning of this, you were pissed off because you were either cheated on, played, lead on, broken up with, or he found another girl, hence the word jackasshole.
He totally just used her.
He's a jackasshole-
Nick spent most of the day making coworkers do the work he is unable to do, in a word he's a Jackasshole.
When you don’t just call someone a jackass or asshole, you combine both into a double swear word.
Person 1: “Yo this person is being a jackasshole”. Person 2: “What the fuck did you just say”.