Richard Soule, A Dictionary of English Synonymes and Synonymous or Parallel Expressions
“ Strengthen, fortify, animate, give vigor to, give life and energy to. Invincibility, n. Unconquerableness, invincibleness. Invincible, a. 1. Unconquerable, not to be subdued. 2. Insuperable, insurmountable, not to be overcome. Invincibleness, n. ”
