I am not english so be kind, from the French, I would say : succinct : would be my first choice, brief, concise, expressed with very little words.

I don't think you can find the perfect opposite for "too many words", because with "not enough words" you can't really express anything but meaningless sentences... :) Maybe with "an explanation being too brief"

Also we have "condensé" in French, don't know if you can say "condensed" in English, as something with a higher density...

I am not English so be kind. But from French, I would say succinct would be my first choice, brief, concise, expressed with very little words.

I don't think you can find the perfect opposite for "too many words", because with "not enough words" you can't really express anything but meaningless sentences. Maybe with "an explanation being too brief"

Also we have condensé in French, don't know if you can say condensed in English, as something with a higher density.