Verb. "to mosby someone". Telling someone (usually on your first date) that you love them in order to freak them out and deter them from having a further relationship with you.
Originates from the show How I Met Your Mother.
Robin: "I found out Barney loves me, what am I gonna do? It's gonna break his heart when I tell him I don't love him back."
Marshall: "Well, there's an option. High risk but high reward. You could mosby him."
Lily: "Oh no, she couldn't mosby him."
Marshal: "She could MOSBY THE CRAP OUT OF HIM."