{Completely, Utterly Random}

Ran - dom
/'randem/
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.
Antonyms: Systematic

2. Informal, odd, unusual, or unexpected.
"I find it impossible to not laugh at such a random guy."