Indifferent

1. adjective

   marked by no especial liking or dislike or preference for one thing over another

   “indifferent about which book you would give them”

2. adjective

   (often followed by `to') lacking importance; not mattering one way or the other

   “whether you choose to do it or not is a matter that is quite immaterial (or indifferent)”

   Similar: immaterial

3. adjective

   having only a limited ability to react chemically; chemically inactive

   “inert matter”

   Similar: inert, neutral

4. adjective

   (usually followed by `to') unwilling or refusing to pay heed

   “deaf to her warnings”

   Similar: deaf