heartbreaker

noun5

1. •
   Someone or something that breaks someone's heart.
2. •
   A person, usually attractive, who flirts with or otherwise enamours another person, but does not reciprocate their love.
3. •
   Something that causes sorrow, grief or extreme disappointment.

   • It's a heartbreaker, as I was reminded just now when I went to get the chapter reference, reread it, and started bawling. — 2007
4. •
   A match which ends in defeat for a promising player or team.
5. •
   (old-fashioned) A curl or lovelock.