Datum adjectives are listed in this post. Each word below can often be found in front of the noun datum in the same sentence. This reference page can help answer the question what are some adjectives commonly used for describing DATUM.
above, empirical, first
fixed, fundamental, historical
immediate, important, necessary
new, original, primary
same, single, ultimate
Hope this word list had the adjective used with datum you were looking for. Additional describing words / adjectives that describe / adjectives of various nouns can be found in the other pages on this website.