An erratic state of being characterized by passing, intermittent fits and outbursts, temper tantrums or volatile mood swings, which fluctuate at regular, fairly predictable intervals and whose origin is rooted in hormonal biochemistry.
Since she's pregnant, I guess I'm supposed to forgive her for being so hormonally hijacked, but... dude, that was like The Exorcist back there.
My girlfriend's a totally cool chick the rest of the month, but man, when she's on her rag... makes me wanna leave town for a couple of days. That broad gets straight hormonally hijacked. Invasion Of The Body Snatchers-style.
You almost can't expect teenaged boys to behave as though they're thinking clearly, considering how hormonally-hijacked they become during those formative years.