What is the meaning of -r?

them

denotes the nominative singular of adjectives, masculine a-stem, i-stem, u-stem, and an-stem, as well as feminine ijo-stem nouns

denotes the nominative and accusative plurals of r- and consonant stem nouns

-ed, forms adjectives from nouns

Forms various agent nouns.

Alternative form of -ra

Alternative form of -re

Added to a stem to form a verb expressing a (quickly) repeating action. No longer productive. It can be found in obscured derivatives, e.g. tántorog, kever.

Originally it was added to nouns primarily as a diminutive suffix. Today it can be found only in obscured derivatives, e.g. tompor. No longer productive.

A suffix added to certain preverbs and subordinating conjunctions when these occur with past tense verbs, and in the past/conditional copular form of these preverbs and conjunctions.

Suffix for the indefinite plural form of some of the nouns of the third declension, chiefly if they end in a stressed vowel except -e or -i, or if it ends in an unstressed -e.

Suffix for the present tense, active voice, indicative mood (all persons) for a small number of Swedish verbs which ends in a vowel except -a in the infinitive; formally also for a large part of those verbs which do end in -a in infinitive.

Simple present tense suffix.

Source: wiktionary.org