It was not a random decision to include "casual" in our list. "Random," "casual," and "haphazard" mean determined by accident rather than design. "Random" stresses the lack of a definite aim, fixed goal, or regular procedure, as in "The students discovered a pattern in what seemed to be a random group of symbols." "Casual" suggests working or acting without intention or purpose, as in "At first she was a casual collector but now she is much more serious about her coin collection." "Haphazard" applies to what happens by chance, as in "Books were piled on the desk in a haphazard manner."