informality
noun
absence of ceremony, affability, casualness, ease, easiness, easygoingness, extemporaneousness, familiarity, fellowship, flexibility, freedom, freedom from affectation, friendliness, inexactitude, inexactness, informalness, ingenuousness, inobservance, irregularity, latitude, laxity, liberty, license, lightness, looseness, naturalness, noncompliance, nonconformity, nonobservance, offhandedness, plainness, relaxation, simplicity, slackness, unaffectedness, unassumingness, unceremoniousness, unconstraint, unconventionality, unorthodoxy, unrigorousness, want of formality
Burton's Legal Thesaurus.
William C. Burton.
2006