Nonacerbic

Perhaps the Committee on Accreditation, which under the leadership of Robert Hayes did a masterful job of holding broadly based and yet nonacerbic meetings to discuss the purpose of accreditation, is most strategically positioned to tackle this issue.

Source: wiktionary

This racially/ethnically mixed, mostly 18-year-old, mostly white group of freshmen were able to have a thoughtful, nonacerbic conversation about race relations through a discussion of Tocqueville's ovservations and hypotheses.

Source: wiktionary

Shortly after the midterms in 1966, Nixon carefully assembled a national campaign staff and began projecting a new, friendlier image to the voters—the New Nixon—relaxed, smiling, and nonacerbic.

Source: wiktionary