In order for something to be random it has to lack apparent pattern or predictability.
If a series of numbers doesn’t appear to have any pattern to it, then it is said to be random.
A random sequence of events, symbols or steps often has no order and does not follow an intelligible pattern or combination.
Individual random events are by definition unpredictable, but since they often follow a probability distribution, the frequency of different outcomes over numerous events (or “trials”) is predictable. This means that they cannot be truly random.