Above-mentioned is indeed a single adjective or adjective phrase, whether it has found itself commonly constructed with hyphen, space, or neither.

Is it above-mentioned or abovementioned?

To write clearly and effectively, avoid legal jargon like the word above-mentioned or aforementioned. Instead, use words such as previously, earlier or above. Legal jargon: The above-mentioned documents are available on our website.

How do you use above-mentioned?

Not all sets of points enjoy the above-mentioned proper ties. The above-mentioned doses of the drugs were chosen because they produced the most prominent effects on refractive development. They do so by using the above-mentioned colonial archives to show that conflicts also existed before.