labile

adj

1. Liable to slip, err, fall, or apostatize.
2. Apt or likely to change.

   “Pythagoras [said] that each thing or matter was ever gliding and labile.”

3. Kinetically unstable; rapidly cleaved (and possibly reformed).

   “Certain drugs can be conjugated to polymer molecules with a linkage that is labile at low pH to effect controlled release in a cellular endosome.”

   “Water ligands typically bind metals in a labile fashion and are rapidly interchanged in aqueous solution.”

4. Able to change valency without changing its form; especially, able to be used both transitively and intransitively without changing its form.