Thank you for your question. The concept of 'central conflict' usually relates to literature, and under this umbrella, central conflict is the main problem in a story.
Central conflict is indispensable to any story line, and is usually the core concept of any plot. Most stories follow this general direction, involving a conflict that rises, reaches a climax and is at some point overcome. Once the central conflict is instilled, the rest of the story, including the characters and their roles, are built around this.
Central conflict is usually the most grabbing point of the story, hence why it is integral to any plot. Without a central conflict, the audience will become uninterested since the story line will tend to follow an abstract order, which can become dull and monotonous. The central conflict also has implications for the story and it's characters, as the audience learns motivations and consequences of different actions.
This is a summary of the definition of central conflict.