Random

ran·dom   (răn'dəm)


adj.

1. Having no specific pattern, purpose, or objective: random movements. See synonyms at chance.
2. Mathematics & Statistics. Of or relating to a type of circumstance or event that is described by a probability distribution.
3. Of or relating to an event in which all outcomes are equally likely, as in the testing of a blood sample for the presence of a substance.

idiom:at random

1. Without a governing design, method, or purpose; unsystematically: chose a card at random from the deck.