Igbo has a very limited list of true adjectives. The main distinguishing factor between an adjective and a modifying noun (the latter of which is an abundant category in Igbo) is the fact that adjectives do not undergo the tonal changes of the Associative construction, while modifying nouns do.
As for quantifies, only three are recognized: dum̀, niị̄le, and naàbọ̀ (according to Emenanjo). Like the true adjectives, they retain their inherent tone when used with nominals. As for the first and third, however, when followed by the proximal demonstrative or a relative clause, they change their inherent tone in accordance with the tone rules.
Very obviously, the simple distinction of "adjective" and "noun" does not work in the case of Igbo. True adjectives are distinct from nouns in the Associative Construction, just as they are from relative clauses that would be translated with adjectives in English.
This does beg the question: What should go under adjective, and what should go under noun? Some nouns like nta are mostly used in the Associative Construction, and fulfill a mostly descriptive role, but just aren't adjectives. What should those be called? I feel as though for simplicity's sake those should just be called adjectives.