What is the Latin word for "will", as in "willpower"?

Question

The English noun "will" has a few different meanings. One is the choice or intention to do something, as in "willing" and "free will": Latin voluntās.

Another meaning, though, is more like "resolve" or "mental strength": the force of mind that drives one to do something despite difficulties (as in "willpower", "force of will", "will to live").

How would I express this second meaning in Latin? For example, someone might have the desire to start something, but lack the willpower to follow through on it. What is the Latin word for what they lack?

Answer 1

Not sure if I get the distinction in all its depth, but here's my attempt at answering. Please correct me if I'm wrong.

The two sources I cite are the fruit of the bibliographic work by Calvin G. Normore in this book.

• One could use voluntas, as Saint Augustine:

  Interest autem qualis sit voluntas hominis; quia si perversa est, perversos habebit hos motus; si autem recta est, non solum inculpabiles, verum etiam laudabiles erunt. Voluntas est quippe in omnibus; immo omnes nihil aliud quam voluntates sunt. Nam quid est cupiditas et laetitia nisi voluntas in eorum consensione quae volumus? Et quid est metus atque tristitia nisi voluntas in dissensione ab his quae nolumus? (De Civitate Dei, XIV, VI)

  But the character of the human will is of moment; because, if it is wrong, these motions of the soul will be wrong, but if it is right, they will be not merely blameless, but even praiseworthy. For the will is in them all; yea, none of them is anything else than will. For what are desire and joy but a volition of consent to the things we wish? And what are fear and sadness but a volition of aversion from the things which we do not wish? (Schaff et al.)

• Also there is an instance of voluntas vivendi by Robert Grosseteste (XIII century):

  Item, qui mentitur ob timorem mortis duas habet voluntates, unam vivendi et alteram non mentiendi. Sed voluntas vivendi maior est reliqua et superat reliquam, et, ut videtur, mentiri cogit.

Note that this is also suggested in the answers to the question linked by fdb.

Another word that comes to mind by reading the quote of St. Augustine is cupiditas, though its connotation is ambiguous (i.e., it may be read in a good or a bad sense).

Answer 2

About a month and a half later, I stumbled across another possibility for this! (Which is useful, since I was trying to draw a distinction between "the desire to do something" and "the resolve to do something", both of which could be voluntas.)

From LSJ on Animus:

The power of willing, the will, inclination, desire, purpose, design, intention (syn.: voluntas, arbitrium, mens, consilium, propositum)

With a particular note:

inducere in animum or animum, to resolve upon doing something