§234. Primary Suffixes

Examples of primary stem-suffixes are:—

I. Vowel suffixes:—

• o- (M., N.), ā- (F.), found in nouns and adjectives of the first two declensions: as, sonus, lūdus, vagus, toga (root TEG).
• i-, as in ovis, avis; in Latin frequently changed, as in rūpēs, or lost, as inscobs ( scobis, root SCAB).
• u-, disguised in most adjectives by an additional i, as insuā-vis (for †suādvis, instead of †suā-dus, cf. ἡδύς), ten-uis (root TEN in tendō), and remaining alone only in nouns of the fourth declension, as acus (root AK, sharp, in ācer, aciēs, ὠκύς), pecū, genū.

II. Suffixes with a consonant:—

• to- (M., N.), tā- (F.), in the regular perfect passive participle, as tēctus, tēctum; sometimes with an active sense, as in pōtus, prānsus; and found in a few words not recognized as participles, as pūtus (cf. pūrus), altus ( alō).
• ti- in abstracts and rarely in nouns of agency, as messis, vestis, pars, mēns. But in many thei is lost.
• tu- in abstracts (including supines), sometimes becoming concretes, as āctus, lūctus.
• no- (M., N.), nā- (F.), forming perfect participles in other languages, and in Latin making adjectives of like participial meaning, which often become nouns, as māgnus, plēnus, rēgnum.
• ni-, in nouns of agency and adjectives, as īgnis, sēgnis.
• nu-, rare, as in manus, pīnus, cornū.
• mo- (mā-), with various meanings, as inanimus, almus, fīrmus, forma.
• vo- (vā-) (commonly uo-, uā-), with an active or passive meaning, as in equus ( equos), arvum, cōnspicuus, exiguus, vacīvus ( vacuus).
• ro- (rā-), as in ager (stem ( ag-ro-), integer (cf. intāctus), sacer, plērī-que (cf. plēnus, plētus).
• lo- (lā-), as in caelum (for † caed-lum), chisel, exemplum, sella (for † sedla).
• yo- (yā-), forming gerundives in other languages, and in Latin making adjectives and abstracts, including many of the first and fifth declensions, as eximius, audācia, Flōrentia, perniciēs.
• ko- (kā-), sometimes primary, as in paucī (cf. παῦρος), locus (for stlocus). In many cases the vowel of this termination is lost, leaving a consonant stem: as,apex, cortex, loquāx.
• en- (on-, ēn-, ōn-), in nouns of agency and abstracts: as, aspergō, compāgē (-ĭnis), gerō (-ōnis).
• men-, expressing means, often passing into the action itself: as, agmen flūmen, fulmen.
• ter- (tor-, tēr-, tōr-, tr-), forming nouns of agency: as, pater (i.e. protector), frāter (i.e. supporter), ōrātor.
• tro-, forming nouns of means: as, claustrum (CLAUD), mūlctrum (MULG).
• es- (os-), forming names of actions, passing into concretes: as, genus ( generis), tempus (see § 15. 4). The infinitive in -ere (as in reg-ere) is a locative of this stem ((--er-e for †-es-i).
• nt- (ont-, ent-), forming present active participles: as, legēns, with some adjectives from roots unknown: as, frequēns, recēns.

The above, with some suffixes given below, belong to the Indo-European parent speech, and most of them were not felt as living formations in the Latin.