A Short Grammar of Classical Greek: Part II: Inflection II: Comparison of Adjectives.

II: COMPARISON OF ADJECTIVES.

1. Comparison is mostly expressed
by ‑τερος, ‑τέρα, ‑τερον in the comparative degree,
by ‑τατος, ‑τάτη, ‑τατον in the superlative degree.

These endings are joined to the stem of the masculine.

Examples:

δίκαιος just, st. δικαιο‑ → δικαιό‑τερος, δικαιό‑τατος,
μέλας black, μελαν‑ → μελάν‑τερος, μελάν‑τατος,
σαφής clear, σαφεσ‑ → σαφέσ‑τερος, σαφέσ‑τατος,
εὐκλεής renowned, εὐκλεεσ‑ → εὐκλεέσ‑τερος, εὐκλεέσ‑τατος.

2. The stems in ‑ο lengthen this vowel to ‑ω, whenever the preceding syllable is short.

Examples:

δεινός terrible → δεινό‑τερος, δεινό‑τατος,
ἔντιμος honored → ἐντιμό‑τερος, ἐντιμό‑τατος,
πικρός bitter → πικρό‑τερος, πικρό‑τατος,
ἔνδοξος renowned → ἐνδοξό‑τερος, ἐνδοξό‑τατος,

but:

σοφός wise → σοφώ‑τερος, σοφώ‑τατος,
ἄξιος worthy → ἀξιώ‑τερος, ἀξιώ‑τατος,
πολεμικός warlike → πολεμικώ‑τερος, πολεμικώ‑τατος.

3. The following adjectives drop their stem characteristic ‑ο:

γεραιός old → γεραί‑τερος, γεραί‑τατος,
φίλος dear → φίλ‑τερος, φίλ‑τατος.

4. ‑έσ‑τερος and ‑έσ‑τατος are added to the stem

a) of the adjectives in ‑ων, ‑ον:

εὐδαίμων happy → εὐδαιμον‑έσ‑τερος, εὐδαιμον‑έσ‑τατος,
σώφρων wise → σωφρον‑έσ‑τερος, σωφρον‑έσ‑τατος.

b) of the contracted adjectives in (‑οος), ‑ους, after dropping the final stem vowel:

ἁπλοῦς simple, st. ἁπλο‑ο‑ → ἁπλούστερος, ἁπλούστατος,
εὔνους well‑disposed, εὐνο‑ο‑ → εὐνούστερος, εὐνούστατος,

from ἁπλο‑έσ‑τερος, εὐνο‑έσ‑τατος, etc.

c) of ἐρρωμένος strong, which also drops final ‑ο: ἐρρωμεν‑έσ‑τερος, ἐρρωμεν‑έσ‑τατος.

Note. — Adjectives often form their comparative by prefixing μᾶλλον magis, more to the positive, and their superlative by μάλιστα maxime, most.

Examples: μᾶλλον φίλος = φίλτερος, μάλιστα σοφός = σοφώτατος, etc.

1. Comparison is less frequently expressed by
-ίων, ‑ίων, ‑ῖον, stem ‑ιον‑, in the comparative,
‑ιστος, ‑ίστη, ‑ιστον, stem ‑ιστο‑, in the superlative.

2. Besides the irregular adjectives (§ 58) there are especially six other adjectives in Greek prose that follow this manner of comparison. Three of them drop the final vowel of their stems before the endings, three form their degrees from a kindred stem:

κακός bad → κακίων, κάκιον, κάκιστος, 3,
ἡδύς sweet → ἡδίων, ἥδιον, ἥδιστος, 3,
ταχύς quick → θᾱ́ττων, θᾶττον, τάχιστος, 3 (θᾱ́ττων from ταχ‑jων).

The comparative and superlative of the following adjectives are derived from one or more stems, which differ from that of the positive degree.

1. ἀγαθός good

ἀμείνων, ἄμεινον, ἄριστος, 3 (clever, brave, ἀρετή),
βελτίων, βέλτιον, βέλτιστος, 3 (morally good, virtuous),
κρείττων, κρεῖττον, κράτιστος, 3 (strong, superior, τὸ κράτος).

2. κακός bad

κακίων, κάκιον, κάκιστος, 3 (worse, peior),
χείρων, χεῖρον, χείριστος, 3 (less good, deterior),
ἥττων, ἧττον, ἥκιστα (adv.) least (weaker, inferior).

3. μέγας great → μείζων, μεῖζον, μέγιστος, 3.

4. μικρός small → μικρότερος, 3, μικρότατος, 3; ἐλάττων, ἔλαττον, ἐλάχιστος, 3.

5. ὀλίγος little → ἐλάττων, ἔλαττον, ἐλάχιστος, 3; μείων, μεῖον.

6. πολύς much → πλείων, πλέον, πλεῖστος, 3 (πλέως, τὸ πλῆθος), genit. etc. πλείονος and πλέονος.

7. ῥᾴδιος easy → ῥᾴων, ῥᾷον, ῥᾷστος, 3 (facilis).

Note. — Defective comparatives are:

(πρό before) → πρότερος prior, πρῶτος primus;
(ὑπέρ above) → ὑπέρτερος superior, ὑπέρτατος supremus;
– ὕστερος posterior, ὕστατος postremus;
(ἐξ out) → ἔσχατος extremus.