Of, relating to, or characterized by conspiracy; inclined to conspire.
From conspire + -ative (adjective suffix meaning 'tending to' or 'relating to'). This is another adjective form alongside conspiratorial and conspirational.
English has at least four different adjective forms from 'conspire': conspiratorial, conspiratory, conspirational, and conspirative—a perfect example of English's love of multiple options for describing the same concept.
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