Anti-conventional

conforming or adhering to accepted standards, as of conduct or taste:
conventional behavior.
pertaining to convention or general agreement; established by general consent or accepted usage; arbitrarily determined:
conventional symbols.
ordinary rather than different or original:
conventional phraseology.
not using, making, or involving nuclear weapons or energy; nonnuclear:
conventional warfare.
art.

in accordance with an accepted manner, model, or tradition.
(of figurative art) represented in a generalized or simplified manner.

of or relating to a convention, agreement, or compact.
law. resting on consent, express or implied.
of or relating to a convention or -ssembly.
historical examples

verestchagin, russian painter, is realistic to an extreme degree and anti-conventional; b. 1842.
the nuttall encyclopaedia edited by rev. james wood

adjective
following the accepted customs and proprieties, esp in a way that lacks originality: conventional habits
established by accepted usage or general agreement
of or relating to a convention or -ssembly
(law) based upon the agreement or consent of parties
(arts) represented in a simplified or generalized way; conventionalized
(of weapons, warfare, etc) not nuclear
noun
(bridge) another word for convention (sense 7)
adj.

late 15c., “of the nature of an agreement,” from late latin conventionalis “pertaining to convention or agreement,” from latin conventionem (see convention). meaning “of the nature of a convention” is from 1812, now rare; “established by social convention” is from 1761; that of “following tradition” is from 1831; that of “non-nuclear” is from 1955. realted: conventionality; conventionally.