disposable (adj.)

1640s, "that may be done without;" see dispose + -able. Sense of "free to be used as the occasion may require, available" is from 1650s. Meaning "designed to be discarded after one use" is from 1943, originally of diapers, soon of everything; replaced throw-away (1928) in this sense. First recorded use of disposable income (which preserves the older sense) is from 1766.