1. Marked by firm determination or resolution; not shakable
   "a man of unbendable perseverence"
   - firm, steadfast, steady, stiff, unfaltering, unshakable, unwavering, unshakeable

See also: resolute

• heteromorphic
• Heteromyidae
• heteronomous
• heteronomy
• heteronym
• heterophil antibody
• heterophil test
• heterophile antibody
• heterophony
• heterophyllous
• heteroplasty
• heteroploid
• heteroploidy
• Heteroptera
• heteropterous insect
• Heteroscelus
• Heteroscelus incanus
• heterosexism
• heterosexual
• heterosexual person
• heterosexualism
• heterosexuality
• heterosis
• Heterosomata
• heterosporous