in·dom·i·ta·ble 
(
ĭn-d
ŏm
ĭ-t
ə-b
əl)
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.