ran·dom
ˈrandəm/Submit
adjective
1.
made, done, happening, or chosen without method or conscious decision.
"a random sample of 100 households"
synonyms: unsystematic, unmethodical, arbitrary, unplanned, undirected, casual, indiscriminate, nonspecific, haphazard, stray, erratic; More
2.
informal
odd, unusual, or unexpected.
"I find it impossible to not laugh at such a random guy"