Herbert Weir Smyth, A Greek Grammar for Colleges

a. Substantives denoting actions often express abstract idea and names of actions and verbal abstracts are often used co<*> cretely. The following suffixes (except μο, nominative -μό-ς, an ες, nominative -ος) form feminines; all are primary except ια_ i<*> some words.

1. τι (nom. -τι-ς): πίσ-τι-ς faith (πείθ-ω persuade, πιθ-), φά-τι-ς rumour (φη<*> say, φα-).

2. σι (nom. -σι-ς): λέξις style (λέγ-ω speak), ποίη-σι-ς poetry (ποιέ-ω make) φθί-σι-ς decay (φθί-ν-ω decay), δό-σι-ς act of giving or gift (δί-δω-μι giv<*> δο-, δω-), θέ-σι-ς placing (τί-θη-μι place, θε-, θη-), τά-σι-ς tension (fo<*> τṇ-σι-ς 35 b, from τείνω stretch, τεν-). σι is derived from τι after vowel (115).

3. σια_ (nom. -σία_): in substantives from verbs in -αζω out of -αδ-ῖω; a<*> δοκιμασία_ examination (δοκιμάζω examine, δοκ μαδ-).

4. τυ (nom. -τύ_-ς 863 a. 17): rare, poetic and dialectic, ἐδ-η-τύ_ς eating (poet<*> ἔδ-ω eat), βοη-τύ_-ς shouting (βοά-ω shout).

5. μο (nom. -μό-ς, masc.): διωγ-μό-ς pursuit (διώκ-ω pursue), πταρ-μό-ς sneez<*> ing (πτάρ-νυ-μαι sneeze). On θ-μο see 832, σ-μο 836, τ-μο 837. Cp 861. 1.

6. μα_ (nom. -μη): γνώ-μη knowledge (γι-γνώ-σκω know), φή-μη report, omen (φη-μί say), τι_-μή honour (poet. τί_-ω honour), μνή-μη memory (μι-μνῄ-σκω remind). See also 861. 1.

7. μα_ (nom. -μα^): τόλ-μα daring (τλῆ-ναι dare).

8. ες (nom. -ος, neut.): δέ-ος fear, ῥῖγ-ος cold.

9. ια_ (nom. -ία_): primitive, from verb-stems, as μαν-ία_ madness (μαίνομαι rage, μαν-). Denominative: ἡγεμον-ία_ sovereignty (ἡγεμών leader), εὐεργεσία kind service (εὐεργετ-ια from εὐεργέτης doer of good deeds). Without any noun-stem: πολιορκία_ siege (πολιορκέω besiege). Verbs in -ευω derived from substantives, as παιδεύ-ω educate (παῖς child), show abstracts in -εία_ for ε（ῦ）-ια_ (43): παιδεία_ education, στρατεία_ campaign (στρατεύομαι take the field), βασιλεία_ reign, kingdom (βασιλεύ-ω am king).

10. ο, α: see 859. 1, 2.

b. Many feminine substantives expressing the abstract notion of the adjective are derived from adjective stems (a few from substantive or verb stems). Many of these denominatives express quality, cp. Eng. -ness, -hood.

1. ια_ (nom. -ια^): from adjectives in -ης and -οος, -ους, as ἀλήθεια truth for ἀληθεσ-ια from ἀληθής true; ἔνδεια want for ἐνδε（ε）σ-ια from ἐνδεής needy, 44 a, 292 d; εὔνοια kindness for εὐνο（ο）-ια from εὐνοο-ς εὔνους kind.

2. ια_ (nom. -ία_): εὐδαιμον-ία_ happiness (εὐδαίμων happy), συμμαχία_ alliance (σύμμαχος fighting along with), σοφ-ία_ wisdom (σοφό-ς wise). Since τ becomes ς before ια_ we have ἀθανασία_ immortality (ἀθάνατο-ς immortal). Cp. 859. 6.

3. συνα_ (nom. -σύνη): δικαιο-σύνη justice (δίκαιο-ς just). Abstracts in -συνη are properly fem. of adj. in -συνος, as γηθο-σύνη joy (γηθό-συνος joyful). -οσύνη by analogy in μαντ-οσύνη art of divination (μάντι-ς seer). See 865. 7.

4. τητ (nom. -της): φιλό-της, -τητος friendship (φίλο-ς friend), ἰσό-της, -τητος equality (ἴσο-ς equal), νεό-της youth (νέο-ς young), παχύ-της thickness (παχύ-ς thick).

5. αδ (nom. -άς): abstract substantives of number, as τρι-άς, -άδος triad (τρεῖς). μον-άς, -άδος unit (μόνο-ς alone, single). See also 863 b. 8.

c. Some neuter abstracts express quality: τάχ-ος speed (ταχ-ύ-ς swift), εὖρ-ος width (εὐρ-ύ-ς broad). See 840 a. 8.

d. A feminine adjective is used substantively in poet. πινυτή wisdom from πινυτό-ς wise; with recessive accent in ἔχθρα_ enmity from ἐχθρό-ς hostile, θέρμη warmth from θερμό-ς warm.

e. Some compound adjectives in -ής yield (by analogy) abstracts in -ια_ not in -εια^; as ἀτυχία_ misfortune from ἀ-τυχ-ής unfortunate. Fluctuation often occurs, as in κακοήθεια κακοηθία_ malignity from κακο-ήθης ill-disposed; Old Attic ἀληθεία_ ( = Ion. ἀληθείη) for ἀλήθεια.