I don't think there is a regularly-used, modern English word that means "too few words to convey meaning". There is, however, one word that does mean that, albeit as a rarely-used meaning in modern use.
That word is elliptic. Elliptic, as Merriam-Webster defines it, has two principal meanings:
1: of, relating to, or shaped like an ellipse
2
a : of, relating to, or marked by ellipsis or an ellipsis
b (1) : of, relating to, or marked by extreme economy of speech or writing (2) : of or relating to deliberate obscurity (as of literary or conversational style)
It definitely has the sense of concision and omission of important detail. "An elliptic report", to my mind, would be one that was not thorough or complete, perhaps leaping to conclusions without sufficient justification, etc.
With all that said, however, for most people elliptical would refer to the shape.
sparse
worked for me as an antonym