Tending to cause or capable of causing asphyxia; having the quality of suffocating or depriving oxygen.
From 'asphyxiate' plus the suffix '-ive' (having the quality of), creating an adjective that describes something's potential to cause suffocation.
This word is rare enough that most people haven't heard it, but it's the perfect technical term for anything designed or likely to cause suffocation—from toxic gases to industrial safety contexts.
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