What is the meaning of the expression "time conflict"?
It means that you have two events or appointments at the same time, so it creates a problem.
If someone had a time conflict, they have "double-booked". They have planned things at the same time, or too close together to make it feasible.
See these examples:
Lydia has a time conflict because she scheduled a meeting the same time that she has a doctor's appointment.
I have a time conflict that day, can we meet next week instead?
Joe needs to take two classes at the same time, so he is in a time conflict.
Hope this helps!