Arbitrary (adjective)

1. Based on random choice or personal whim, rather than any reason or system.
2. Decided by a person rather than by rules.

Origin:

Late 16th century: from latin arbitrarius, from arbiter "judge, umpire", from arbitrium "choice, discretion".

Examples:

1. The decision was arbitrary and had no basis in fact.
2. The punishment was arbitrary and unjust.
3. His actions were arbitrary and capricious.
4. The rule is arbitrary and can be changed at any time.
5. The decision was arbitrary and not based on any evidence.