Classical Adûnaic nouns are either formed directly from roots or by suffixion/prefixion, though direct root-derivation is rare save for Neuter-nouns (and even rarer for Feminine-nouns). They end in either a vowel or single consonant like all Adûnaic words, as consonant clusters are forbidden for all except medial consonants.
Classical Adûnaic nouns follow a “two-vowel” minimum rule and must have at least two consonants in Root form. Any exceptions to the latter rule is due to a consonant being lost due to it being dropped from the language entirely (Êru < √ʔIR).