undull adjective 1verb 1forms 5 adjective1 •Not dull; sharp. verb1 •To make less dull (various senses).It is a most musicall Modulator of all Intelligibles by her inventive Variations, undulling their Grossenesse, and subliming it into more refined Acceptablenesse to our own, or others understandings. — 1654 formsundulled · undulling · undulls · more undull · most undull