Is it ensure, insure, or assure?
1560s, from Middle French friable and directly from Latin friabilis "easily crumbled or broken," from friare "rub away, crumble into small pieces," related to fricare "to rub" (see friction). Related: Friability.
friable fri·a·ble (frī'ə-bəl)
Readily crumbled; brittle.
Relating to a dry, brittle growth of bacteria.