To fall apart means to break into pieces or stop working properly. When your favorite stuffed animal falls apart after years of hugs, its seams rip and the stuffing comes out. When an old book falls apart, pages loosen and the spine cracks. Things fall apart through wear, age, or damage.

The phrase also describes what happens when plans, organizations, or situations collapse. A carefully built tower of blocks might fall apart with one wrong move. A friendship can fall apart when people stop communicating or trust breaks down. A soccer team's strategy might fall apart in the final minutes of a tough game when players get too tired to execute their plays.

People sometimes say they're falling apart when they feel overwhelmed or unable to cope with stress. A student might feel like they're falling apart during a difficult week with multiple tests and projects due. This usage captures that sense of things breaking down or coming undone, whether it's an object losing its structure or a person losing their composure. The opposite would be holding together or staying calm under pressure.