adj. Incapable of being subdued, overcome, or vanquished.
the GNU version of the Collaborative International Dictionary of English
adj. Not to be subdued; untamable; invincible.
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.
WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
adj. 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.""