Fell out means to have an argument or disagreement, often resulting in a damaged relationship. It can also mean to fall out of something or somewhere, but this physical meaning is less common.
The phrase "fell out" is a past tense form of "fall out," which typically describes a verbal conflict. For example, "They fell out over money" means they had a serious argument about financial issues. This usage is informal but widely understood.
There are two primary meanings:
Most often, "fell out" describes a falling-out between people. For instance, "After years of friendship, they fell out over politics" suggests a long-term rift caused by political differences. Another example: "The siblings fell out during the holiday dinner, ruining the celebration."
Less commonly, it describes a physical fall. For example, "The books fell out of the shelf when the cat jumped onto it." However, this usage is usually replaced by "fell off" or "fell down."
People often confuse "fell out" with "fell down" or "fell off." While "fell out" can describe a physical fall, it's more likely to refer to an argument. For example, saying "She fell out of the car" is correct but unusual; "she fell out with her friend" is far more common.
Another mistake is using "fell out" to describe a minor disagreement. The phrase implies a significant conflict, not just a small argument. For example, "They fell out over who should do the dishes" suggests an intense fight, not a casual disagreement.
I once witnessed a heated debate between two coworkers over project deadlines. Their disagreement escalated quickly, and they fell out, refusing to speak to each other for weeks. This situation perfectly illustrates how "fell out" describes a serious argument that damages relationships.