dispensable (adj.)

1530s, "subject to (ecclesiastical) dispensation, excusable, pardonable," from Medieval Latin dispensabilis, from Latin dispensare "disburse, administer, distribute (by weight)" (see dispense).

Meaning "that can be done without" is from 1640s; that of "capable of being administered" is from 1670s. Later senses in some cases might be directly from dispense. Related: Dispensability.