haphazard
adjective
things were strewn around in a haphazard fashion:
random, unplanned, unsystematic, unmethodical, disorganized, disorderly, irregular, indiscriminate, chaotic, hit-and-miss, arbitrary, orderless, aimless, undirected, careless, casual, slapdash, slipshod;
chance, accidental;
informal higgledy-piggledy.
▷antonyms methodical; systematic.
haphazard Oxford Dictionary of English