粗野|そやsoya[1]atamadaka (head-high)

1. na-adjective, nounrustic; rude; vulgar; rough
   あの長髪ちょうはつの青年せいねんは粗野そやだ。↗

   That long-haired youth is rude.

• Synonym下品げひんNeutralThe most common everyday word for something indecent or dirty—speech, table manners, jokes. 「粗野」 is about rough, uncouth behavior rather than obscenity.
• Synonym無作法ぶさほうNeutralLack of manners or etiquette; rude but not necessarily rough or vulgar. The focus is on breaches of etiquette.
• Synonym無礼ぶれいNeutralDisrespect or discourtesy toward people, especially superiors; about etiquette. Can overlap with 「粗野」, which stresses rough, vulgar conduct.
• Synonym非礼ひれいWrittenWritten/formal. A breach of etiquette, mostly seen in writing, as in 「非礼を詫びる」.
• Synonym失敬しっけいNeutralRudeness, but also a casual (male) way to say goodbye or to take something without asking; lighter in tone than 「粗野」.
• Synonym野暮やぼNeutralBoorish in the sense of being out of touch, unfashionable, or unable to take a hint—unrefined rather than rough.
• Synonym低俗ていぞくNeutralLowbrow and tacky; typically judges TV shows and entertainment content.
• SynonymはしたないNeutralImproper or unseemly behavior, often a woman's; as in 「はしたない真似」.
• Synonym無骨ぶこつNeutralRugged and unpolished, lacking refinement; often carries a hint of honest simplicity and is not always negative.
• Synonym野卑やひWrittenWritten/formal. Stresses coarse, vulgar speech and behavior, with a stronger sense of lowness; 「粗野」 centers on rough, unrefined conduct.
• Synonym卑俗ひぞくWrittenWritten/formal. Lowbrow and lacking in taste; often used to judge works of art or literature and people's tastes.
• Synonym俗悪ぞくあくWrittenWritten/formal. Vulgar and distasteful; typically judges publications and TV or radio programs.
• Synonym低級ていきゅうNeutralLow in grade or quality; also lowbrow taste. Mostly describes things rather than people's behavior.
• Synonym不行儀ふぎょうぎNeutralImproper, ill-bred behavior; often said of children or of posture, e.g. sitting badly.
• SynonymがらっぱちCasualColloquial, with an old Edo flavor. A person who is rude in speech and behavior.
• Related卑劣ひれつNeutralDespicable means or sneaky conduct; condemns moral corruption, not rough manners.
• Related無遠慮ぶえんりょNeutralBlunt and presumptuous, with no regard for the other person; not necessarily vulgar.
• Related陋劣ろうれつWrittenWritten/formal and dated. A base, mean character; the focus is moral lowness, not rough manners.
• Antonym上品じょうひんNeutralAntonym: elegant, tasteful conduct—the opposite of rough, unrefined behavior.
• Antonym優雅ゆうがNeutralAntonym: graceful and composed; the opposite of 「粗野」, and can also describe a leisurely life.

For everyday indecency choose 「下品」; for rudeness toward people, 「無礼」 or 「無作法」. Use 「粗野」 itself for rough, uncouth behavior, 「無骨」 for rugged simplicity, and 「低俗」 for lowbrow works or content. Most others are narrower or written/formal: 「野卑」「卑俗」「俗悪」「陋劣」 in formal prose, 「がらっぱち」 colloquial for a rude person, and 「上品」「優雅」 as antonyms.

Usage comparisons are AI-assisted and cross-checked by multiple models; for study reference only

1. 言葉遣ことばづかいや行動こうどうが乱暴らんぼうで卑いやしいこと。また、そのようなさま。