Synonyms for Natural:

adj.

animal (adjective)
untamed.
artless (adjective)
artless, blunt, broad, callow, candid, direct, downright, frank, genuine, honest, ingenuous, naive, open, outgoing, overt, plain, sincere, straightforward, trusting, unadorned, unaffected, undisguised, unpretentious, unrestrained, unsophisticated, Plain-spoken, Unartful, Unbeguiling, un-artificial, uncalculating, undeceitful, undeceiving, undeceptive.
good-humored (adjective)
easy.
habitual (adjective)
habitual.
lifelike (adjective)
exact, faithful, lifelike, realistic, vivid.
material (adjective)
concrete, corporeal, material, objective, palpable, physical, real, solid, substantial, tangible, worldly.
normal, everyday (adjective)
accustomed, anticipated, characteristic, common, connatural, consistent, constant, customary, general, habitual, indigenous, innate, instinctive, involuntary, legitimate, logical, ordinary, prevailing, prevalent, probable, reasonable, regular, spontaneous, typical, uncontrolled, uniform, universal, usual, Familiar.
open, unaffected (adjective)
artless, candid, childlike, credulous, direct, easy, folksy, forthright, frank, genuine, homey, impulsive, ingenuous, innocent, laid-back, naive, plain, real, rustic, simple, sincere, straightforward, trusting, unfeigned, unpolished, unpretentious, unsophisticated, unstudied, unworldly.
organic, unrefined (adjective)
raw, unbleached, uncultivated, undomesticated, unprocessed, wild.
plainspoken (adjective)
Plain-spoken.
simple (adjective)
artless.
untamed (adjective)
wild.

n.

alien, bass, beat, chord, crotchet, foreign, fundamental, genetic, incarnate, inherited, original, true, B, C, D, double flat, DO. accepted, accustomed, anticipated, characteristic, common, consistent, constant, customary, decent, expected, fair, fair-minded, general, habitual, independent, involuntary, just, legitimate, logical, ordinary, predictable, prevailing, prevalent, probable, reasonable, regular, routine, typical, unbiased, uncontrollable, uncontrolled, unexpected, uniform, universal, unusual, usual, wonted, Familiar, matter of course. artist, best, childlike, credulous, exponent, forthright, homey, impulsive, innocent, maestro, master, old hand, past master, prodigy, queen, rustic, simple, superman, unfeigned, unpolished, unpretentious, unstudied, unsuspecting. actual, adaptive, addictive, babyish, classy, constitutionally, flawed, flexible, Clingy, badass. culture, fine, good, irreproachable, organic, principled, unadulterated, upstanding. basic, core, rough, rudimentary, uncultivated, undomesticated, untamed, wild. be, built-in, connatural, constitutional, dad, daddy, deadbeat dad, father, fatherhood, indigenous, start, empty nester, birth father, birth mother, birth parent, custodial parent. civilized, comfortable, comfy, folksy, heartfelt, hearty, intimate, luxurious, salubrious, snug, unmannered, warm. ecology, ecosystem, element, guileless, natural resources, nature, resource, unworldly, raw materials, the biosphere, the environment. casual, easy, easygoing, informal, laid-back, relaxed, tighten, unceremonious. homely, homespun, unadorned. naturalistic, truthful, true-life. baseborn, illegitimate, kin, law, misbegotten, spurious, unlawful. natural (noun)
biological, born, cancel, earthy, elemental, fresh, innate, instinctive, intelligent, lifelike, normal, physical, raw, rude, self-generated, spontaneous, unaffected, unbleached, uncolored, undyed, unprocessed.

Other synonyms:

accepted, baseborn, connatural, easy, fair-minded, just, laid-back, naturalistic, regular, unbiased, uncultivated, undomesticated, untamed, Familiar, true-life. built-in, easygoing, guileless, heartfelt, hearty, homespun, illegitimate, independent, innocent, legitimate, reasonable, rustic, unadorned, unadulterated, unceremonious, unfeigned, unstudied, wild. fair, homely, relaxed, truthful. core, unlawful. spurious, unworldly. basic, unpolished. simple. true. rough. baseborn
misbegotten.
commonplace
common.
distinctive
characteristic.
ordinary
usual.
routine
matter of course.
unaffected
childlike.
without formality
informal.
Other relevant words:
accepted, accustomed, actual, alien, anticipated, artist, baseborn, basic, biological, born, built-in, cancel, casual, characteristic, childlike, common, connatural, consistent, constant, constitutional, constitutionally, credulous, crotchet, customary, earthy, easy, easygoing, elemental, expected, folksy, forthright, fresh, fundamental, general, genetic, good, guileless, habitual, heartfelt, hearty, homely, homespun, homey, illegitimate, impulsive, incarnate, indigenous, informal, inherited, innate, innocent, instinctive, intelligent, involuntary, laid-back, legitimate, logical, misbegotten, naturalistic, nature, normal, ordinary, organic, original, predictable, prevailing, prevalent, probable, prodigy, raw, reasonable, regular, relaxed, rough, routine, rude, rudimentary, rustic, self-generated, simple, spontaneous, spurious, true, truthful, typical, unadorned, unadulterated, unbiased, unbleached, unceremonious, uncolored, uncontrolled, uncultivated, undomesticated, undyed, unfeigned, uniform, universal, unlawful, unmannered, unpolished, unpretentious, unprocessed, unstudied, untamed, unworldly, usual, wild, wonted, Familiar, matter of course, true-life.

Usage examples for natural

  1. " I loved this little girl, as it was natural I should, more than I loved the other, whose mother was a servant. – Bad Hugh by Mary Jane Holmes
  2. True; all that would be most natural – Dawn by Mrs. Harriet A. Adams
  3. Well, it's natural he should. – The Judgment House by Gilbert Parker