ἀγαθός
Etym. deriv. uncertain
"good", Lat. bonus:
I. of persons,
1. in early times, "good, gentle, noble", in reference to birth, opp. to κακοί, πατρὸς δ᾽ εἴμ᾽ ἀγαθοῖο, θεὰ δέ με γείνατο μήτηρ Il.; ἀγαθοὶ καὶ ἐξ ἀγαθῶν, Lat. boni bonis prognati, Plat.; with this early sense was associated that of wealth and power, like Lat. optimus quisque in Sallust and Cicero; esp. in the phrase καλοὶ κἀγαθοί (v. καλοκἀγαθός).
2. "good, brave", since these qualities were attributed to the Chiefs, Il.; ἀγαθὸς ἐν ὑσμίνῃ, βοὴν ἀγαθός, πὺξ ἀγαθός, etc., Hom.; ἀγ. τὰ πολέμια, τὰ πολιτικά Hdt., etc.;—also c. dat., ἀγ. πολέμῳ Xen.;—and, ἀγ. εἴς τι, περί τι, πρός τι Plat., etc.; lastly, c. inf., ἀγ. μάχεσθαι, ἱππεύεσθαι, "good" at fighting, etc., Hdt.
3. "good", in moral sense, Plat., etc.
4. ἀγαθοῦ δαίμονος, as a toast, "to the good Genius," Ar.
II. of things,
1. "good, serviceable", Ἰθάκη ἀγαθὴ κουροτρόφος Od.; ἀγ. τοῖς τοκεῦσι, τῇ πόλει Xen.; c. gen., εἴ τι οἶδα πυρετοῦ ἀγ. "good" for fever, id=Xen.; ἀγαθόν [ἐστι], c. inf., "it is good" to do so and so, Hom., etc.
2. ἀγαθόν, τό, "a good", of persons, φίλον, ὃ μέγιστον ἀγ. εἶναι φασι Xen.; ἐπ᾽ ἀγαθῷ τοῖς πολίταις Ar.; τὸ ἀγαθόν or τἀγαθόν, "the good, summum bonum", Plat., etc.; in pl., ἀγαθά, τά, "the goods of fortune, wealth", Hdt., etc.; also "good qualities", of a horse, Xen.
III. instead of the "regular" degrees of comparison, many forms are used,—comp. ἀμείνων, ἀρείων, βελτίων, κρείσσων, λωΐων, epic βέλτερος, λωΐτερος, φέρτερος; — Sup. ἄριστος, βέλτιστος, κράτιστος, λώϊστος, epic βέλτατος, κάρτιστος, φέρτατος, φέριστος.
IV. the adv. is usually εὖ: ἀγαθῶς in late writers.