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δεινόν

Ἐς δὲ τὰ ἔσχατα νουσήματα αἱ ἔσχαται θεραπεῖαι ἐς ἀκριβείην, κράτισται -> For extreme diseases, extreme methods of cure, as to restriction, are most suitable.
Corpus Hippocraticum, Aphorisms 1.6.2

Russian (Dvoretsky)

δεινόν:
I adv. страшно, грозно (ἀϋαι, δέρκεσθαι Hom.).
II τό
1) Aesch. = δεῖμα 1 и 2;
2) возмущение, негодование Her.