to get melancholy or depressed, where some one shows attitude of serenity or becoming cynic. This can be caused by various psychological factor such as long term stress or manic depression.
Ken: Sherryjust found out that her boy friend was cheating with another girl.
Luke: damn, how is she now?
Ken: she's undercooled man.
Someone who jumps from one relationship immediately into another one.
Serial monogamists can not stand to be alone and often suffer from vast commitment and insecurity issues.
Because they jump into relationships immediately after the previous one has ended, serial monogamists typically don't take the time to reflect on their behavior or why their previous relationships failed; thus, they end up making the same relationship mistakes over and over again.
Person 1: Damn, Dustin already has a new girlfriend?! It's only been two weeks since he broke up with his fiance! I think he's a sociopath.