Not reactive or interactive (5)

I believe the answer is:

inert

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'not reactive' is the definition.
(I've seen this before)

I can't explain the remainder of the clue.

(Other definitions for inert that I've seen before include "Lifeless or static" , "Disinclined to move" , "Dormant, lifeless" , "Slow and apathetic" , "Unreactive; still" .)

I've seen this clue in The Guardian.

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