Firmnesses, noun plural of firmness. Synonyms in the same form.
Hardness
hardnesses, strengths, solidities, constancies, stiffnesses, courages, resolutions, determinations, obstinacies, grits, inflexibilities, wills, nerves, decisions, resolutenesses, fortitudes, tenacities, pertinacities
Other
soundnesses, steadinesses, stabilities, hardinesses, strictures
All synonyms for firmness →