nonconforming adj.

a prefix used freely in English and meaning "not, lack of," or "sham," giving a negative sense to any word, 14c., from Anglo-French noun-, from Old French non-, from Latin non "not, by no means, not at all, not a," from Old Latin noenum "not one" (*ne oinom, from PIE root *ne- "not" + PIE root *oi-no- "one, unique"). In some cases perhaps from Middle English non "not" (adj.), from Old English nan (see not). "It differs from un- in that it denotes mere negation or absence of the thing or quality, while un- often denotes the opposite of the thing or quality" [Century Dictionary].

mid-14c., confourmen, "be obedient (to God), comply," from Old French conformer "conform (to), agree (to), make or be similar, be agreeable" (13c.) and directly from Latin conformare "to fashion, to form, to shape; educate; modify," from assimilated form of com "together" (see con-) + formare "to form" (see form (v.)).

Meaning "to make of the same form or character; bring into harmony, make agreeable," and intransitive sense of "act in accordance with an example" are from late 14c. Sense of "to comply with the usages of the Church of England" is from 1610s; hence conformist (1630s), opposed to non-conformist or dissenter. Related: Conformance; conformed; conforming.

also non-conformist, "one who does not conform to some law or usage," 1610s, originally and especially of clergymen who adhered to Church of England doctrine but not its practice, from non- + conformist. After their ejection under the Act of Uniformity (1662) the name passed to the separate churches they joined or formed. In general use from 1670s as "one who does not participate in a practice or course of action." As an adjective from 1640s. Shortened form non-con is attested from 1680s.