Section — Prümmer, Manuale Theologiae Moralis
§ 2. On acedia
565. Acedia is a certain aggravating sadness, namely, one that so depresses the soul that it pleases one to do nothing; and therefore acedia implies a certain weariness of working or a certain torpor of mind neglecting to begin goods.84 Acedia, insofar as it is a special vice, can be defined: disgust and sadness concerning spiritual goods or concerning the means of eternal salvation, on account of the difficulty experienced in acquiring and using them. Taken in this sense, acedia is a mortal sin from its genus, as directly opposed to charity, which not only is not saddened but rather rejoices concerning spiritual and divine goods and fervently pursues them according to that of the Psalm: "I rejoiced at the things that were said to me: We shall go into the house of the Lord."85 Cf. those things said above, n. 434 sqq., concerning the malice, effects, and remedies of acedia.
84 S. theol. 2, 2, q. 35, a. 1.
85 Ps. 121, 1.