-τερος

From Proto-Indo-European *-teros.

-τερος • (-teros) m (feminine -τέρᾱ, neuter -τερον); first/second declension

1. Used on adjectives that express some notion of contrast with an antonym

   ‎ἡμεῖς (hēmeîs, “we”) + ‎-τερος (-teros) → ‎ἡμέτερος (hēméteros, “our”)

2. Added to adjective stems to form comparative forms

   ‎δῆλος (dêlos, “clear”) + ‎-τερος (-teros) → ‎δηλότερος (dēlóteros, “clearer”)

   ‎σοφός (sophós, “wise”) + ‎-τερος (-teros) → ‎σοφώτερος (sophṓteros, “wiser”)

• -ίων (-íōn), -ων (-ōn)

• Smyth, Herbert Weir (1920) “Part II: Inflection”, in A Greek grammar for colleges, Cambridge: American Book Company, § 313

-τερος • (-teros)

1. Added to many adjectives and some adverbs to form the comparative forms.

   ‎βαθύς (vathýs, “deep”) + ‎-τερος (-teros) → ‎βαθύτερος (vathýteros, “deeper”)

   ‎όμορφος (ómorfos, “beautiful”) + ‎-τερος (-teros) → ‎ομορφότερος (omorfóteros, “more beautiful”)

2. Added to many adjectives and some adverbs to form the relative superlative forms.

   ‎βαθύς (vathýs, “deep”) + ‎-τερος (-teros) → ‎ο βαθύτερος (o vathýteros, “deepest”)

• -τατος (-tatos)
• -ερός (-erós)