in·dom·i·ta·ble 
(ĭn-dŏmĭ-tə-bəl)
(ĭn-dŏmĭ-tə-bəl)adj.
Incapable of being overcome, subdued, or vanquished; unconquerable.
[Late Latin indomitābilis : Latin in-, not; see IN-1 + Latin domitāre, to tame, frequentative of domāre, to subdue; see demə- in the Appendix of Indo-European roots.]
in·dom′i·ta·bili·ty, in·domi·ta·ble·ness n.
in·domi·ta·bly adv.