Refers to an unfortunate situation where someone who had begun exhibiting undesirable behavior that others had initially assumed was his "just going through a phase" actually does **not** eventually "taper off", but continues to display said distressing attitude/actions.
My teenage son started being really rude and mouthy at age 12, and our pediatrician had assured me that it was "merely a stage he was going through", and that "he'd outgrow it eventually". Well, that was over six years ago, and if anything the boy's behavior is even more sulkily-resentful and anti-social than ever --- looks like a phase-locked loop to me!
by QuacksO February 1, 2019