The adjectival suffixes -ārius, -tōrius, and -sōrius denote belonging to a group qualified by the implied content of the correspond root. Effectively, these adjectives are formed by the addition to -ius to the adjectival root -āris or the nominal root -or. Let’s build a few examples.
- bellum (war) —> bellātor (warrior) —> bellātōrius, -a, -um (of warriors)
- pecūlium (property) —> pecūliāris, -e (one’s own) —> pecūliārius, -a,- um (of private property)
- meritō (to earn) —> meritus (earned) —> [meritor] (earner) —> meritōrius, -a, -um (profitable, esp. related to prostitution)
- extrā (outside) —> [extrāris, e] (foreign) —> extrārius, -a, -um (of foreigners)
A few things to notice about this pattern: (i) the original base of the adjective can be just about anything—noun, adjective, verb, adverb—but the penultimate word is always a noun or an adjective. That said, (ii) the penultimate noun or adjective is not always extant in Latin; note the [brackets]. Finally, note that (iii) this set of adjectives is often theoretical—rēs bellatōriae (matters of warriors)and rēs extrāriae (matters of foreigners) probably cover half the total appearances of those two adjectives.
Latin for Addicts 