fortitude

Etymology

From Middle English fortitude, from Old French, from Latin fortitūdō (“bravery, strength”), from fortis (“brave, strong”).

noun

1. Mental or emotional strength that enables courage in the face of adversity.
   Mitt Romney […] charges that [Barack] Obama is an appeaser who apologizes for America, lacks fortitude and is "tentative, indecisive, timid and nuanced." 30 January 2012, Fareed Zakaria, “The Strategist”, in Time, archived from the original on 2012-07-26
   The proper fans might also expend time—about twenty hours—trying to visit every Tube station as quickly as possible. […] But to visit every station in record time—which people have been attempting since at least 1960—requires real fortitude. You must get up before dawn, you must drink or eat almost nothing, so niggardly is the Underground with toilet provision. 2012, Andrew Martin, Underground Overground: A Passenger’s History of the Tube, Profile Books, page 267
2. (archaic) Physical strength.