1. fearful, terrible, dread, dire , (Homer), etc.; δεινὸν ἀϋτεῖν, βροντᾶν to shout, thunder terribly , (Iliad by Homer); δεινὸν δέρκεσθαι, παπταίνειν, ἰδεῖν to look terrible , (Homer); but, δεινὸς ἰδέσθαι fearful to behold, (Odyssey by Homer); δεινὸς μὲν ὁρᾶν, δεινὸς δὲ κλύειν (Sophocles Tragicus):—; τὸ δεινόν danger, suffering, awe, terror , (Herdotus Historicus), etc.; so, τὰ δεινά (Sophocles Tragicus), etc.:—; οὐδὲν δεινοί, μὴ ἀποστέωσιν no fear of their revolting, (Herdotus Historicus):—; δεινὸν ποιεῖσθαι to take ill, complain of, be indignant at a thing, Lat. aegre ferre, (Herdotus Historicus), etc.; δεινὰ παθεῖν to suffer dreadful, illegal, arbitrary treatment, attic; so in adverb, δεινῶς φέρειν (Herdotus Historicus); δ. ἔχειν to be in straits , (Xenophon Historicus)

2. with a notion of Force or Power, mighty, powerful , δεινὸν σάκος the mighty shield, (Iliad by Homer)

3. simply, wondrous, marvellous, strange , τὸ συγγενές τοι δεινόν kin has a strange power , (Aeschulus Tragicus); δ. ἵμερος, ἔρως, δέος (Herdotus Historicus); δεινὸν ἂν εἴη, εἰ . it were strange that . (Euripides):—;adverb -νῶς, marvellously, exceedingly , δ. μέλας, ἄνυδρος (Herdotus Historicus)

4. the sense of powerful, wondrous passed into that of able, clever, skilful , (Herdotus Historicus), attic; especially of practical ability , opposite to σοφός, (Plato Philosophus): with infinitive, δεινὸς εὑρεῖν clever at inventing, (Aeschulus Tragicus); δεινὸς λέγειν (Sophocles Tragicus); δεινὸς πράγμασι χρῆσθαι (Demosthenes Orator): also with accusative, δεινὸς τὴν τέχνην (Plato Philosophus); δ. περί τι or τινος (Plato Philosophus) (ML)