in·ex·haust·i·ble 
(ĭn′ĭg-zôstə-bəl)
(ĭn′ĭg-zôstə-bəl)adj.
1. That cannot be entirely consumed or used up: an inexhaustible supply of coal.
2. Never wearying; tireless: an inexhaustible campaigner.
in′ex·haust′i·bili·ty, in′ex·hausti·ble·ness n.
in′ex·hausti·bly adv.