reactive

/R IY0 AE1 K T IH0 V/
adjective
  1. 1

    That reacts or responds to a stimulus

  2. 2

    That readily takes part in reactions

    โ€œfrancium is the most reactive of the alkali metals.โ€

  3. 3

    Characterized by induction or capacitance rather than resistance.

  4. 4

    Reacting to the past rather than anticipating the future, not predictive.

Antonyms

Source: https://en.wiktionary.org/wiki/reactive