adjective.
Incapable of being overcome, subdued, or vanquished; unconquerable.
The Century Dictionary and Cyclopedia
That cannot be tamed, subdued, or repressed; untamable: applied chiefly to human beings and their attributes: as, indomitable energy, obstinacy, courage, etc.
the GNU version of the Collaborative International Dictionary of English
adjective.
Not to be subdued; untamable; invincible.
adjective.
Incapable of being subdued, overcome, or vanquished.
WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
adjective.
impossible to subdue
Word Usage
"Getty Images U.S. forward Abby Wambach Anson Dorrance, who coached the U.S. to its first World Cup win in 1991, said the key to winning that tournament was to tap into the generally superior athletic abilities of the U.S. women and what he calls the "indomitable American spirit and competitiveness.""