unsystematic
adjective
un·sys·tem·at·ic
ˌən-ˌsi-stə-ˈma-tik
: not marked by or manifesting system, method, or orderly procedure : not systematic
an unsystematic polling technique
unsystematically
adverb
He collected unsystematically, without considering fine bindings or rarity value.
—Sarah Bakewell
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Merriam-Webster unabridged
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