difficilis

Arduus (from ὀρθός) means difficult to ascend, in opp. to pronus; on the other hand, difficilis means difficult to execute, in opp. to facilis. Arduus involves a stronger notion of difficulty, and denotes the difficult when it borders on the impossible. Plin. Ep. iv. 17. Est enim res difficilis ardua. Tac. Hist. ii. 76. Æstimare debent, an quod inchoatur, reipublicæ utile, ipsis gloriosum, aut promptum effectu, aut certe non arduum sit. Cic. Verr. i. 51. Cum sibi omnes ad illum allegationes difficiles, omnes aditos arduos, ac pæne interclusos, viderent. (ii. 105.)

1. Austerus (αὐστηρός, from αὔω) denotes gravity as an intellectual, severus (αὐηρός) as a moral quality. The austerus in opp. to jucundus, Plin. H. N. xxxiv. 8. xxxv. 11, is an enemy to jocularity and frivolity, and seeks in science, learning, and social intercourse, always that which is serious and real, at the risk of passing for dull; the severus, in opp. to luxuriosus, Quintil. xi. 3, 74, is rigid, hates all dissoluteness and laxity of principle, and exacts from himself and others self-control and energy of character, at the risk of passing for harsh. The stoic, as a philosopher, is austerus, as a man, severus. 2. Austerus and severus involve no blame; whereas difficilis, morosus, and tetricus, denote an excess or degeneracy of rigor. The difficilis understands not the art of easy and agreeable converse, from hypochondria and temperament; the morosus (from mos) is scrupulous, and wishes everything to be done according to rule, from scrupulosity and want of tolerance; the tetricus (redupl. of trux, τραχύς) is stiff and constrained, from pedantry and want of temper. (iii. 232.)