大|おおoo[1]atamadaka (head-high)

1. prefixlarge; big; great; major; important; serious; heavy; loud
   大口おおぐち叩たたきは何なんもできない。↗

   Great talkers are little doers.
2. prefixolder; senior
3. prefixfinal; ultimate
4. prefixrough; broad; general

• Synonym大きいおおきいNeutralThe all-purpose adjective for big; 「大（おお）」 is a prefix, as in 「大雨」「大騒ぎ」.
• SynonymでかいCasualColloquial and rough-edged way to say big, as in 「でかい家」; 「大（おお）」 is a prefix, as in 「大物」.
• Synonym巨大きょだいWrittenWritten/formal word for enormous, as in 「巨大地震」; 「大（おお）」 is a prefix, as in 「大地震」.
• SynonymおっきいCasualColloquial sound change of 「大きい」, used by adults and children alike and fairly casual; 「大（おお）」 is a prefix.
• Synonym大型おおがたNeutralFor large models or scale, as in 「大型連休」; 「大（おお）」 is a prefix.
• SynonymどでかいCasualColloquial and emphatic: exceptionally huge; 「大（おお）」 is a prefix, as in 「大喜び」.
• Synonym馬鹿でかいばかでかいCasualColloquial and hyperbolic: ridiculously big; 「大（おお）」 is a prefix, as in 「大げさ」.
• Related広範こうはんWrittenWritten/formal: wide-ranging in scope, as in 「広範な影響」; 「大（おお）」 is a prefix.
• Related膨大ぼうだいWrittenWritten/formal: vast in quantity, as in 「膨大なデータ」; 「大（おお）」 is a prefix.
• Related広大こうだいNeutralFor vast expanses of land, as in 「広大な土地」; 「大（おお）」 is a prefix, as in 「大通り」.
• Related大規模だいきぼNeutralFor large scale, as in 「大規模工事」; 「大（おお）」 is a prefix, as in 「大仕事」.
• Related手広いてびろいNeutralFor wide-ranging business or dealings, as in 「手広く商う」; 「大（おお）」 is a prefix.
• RelatedワイドNeutralLoanword for wide, as in 「ワイド画面」; 「大（おお）」 is a prefix, as in 「大型」.
• Related幅広いはばひろいNeutralFor broad ranges, as in 「幅広い年齢層」; 「大（おお）」 is a prefix.
• Related壮大そうだいNeutralFor grand scale or ambitious vision, as in 「壮大な計画」; 「大（おお）」 is a prefix.
• Related絶大ぜつだいWrittenWritten/formal: utmost influence or trust, as in 「絶大な人気」; 「大（おお）」 is a prefix.
• Related甚大じんだいWrittenWritten/formal: extremely severe damage, as in 「甚大な被害」; 「大（おお）」 is a prefix.
• Related莫大ばくだいNeutralFor enormous sums of money, as in 「莫大な費用」; 「大（おお）」 is a prefix, as in 「大損」.
• RelatedおびただしいWrittenWritten/formal: astonishingly numerous, as in 「夥しい数」; 「大（おお）」 is a prefix.
• Related大々的だいだいてきNeutralFor doing things on a grand, high-profile scale, as in 「大々的に宣伝」; 「大（おお）」 is a prefix.
• Related極大きょくだいWrittenWritten/formal: extremely large; in mathematics it means a local maximum; 「大（おお）」 is a prefix, as in 「大当たり」.
• Relatedかさ高いかさだかいNeutralFor bulky things that take up space, as in 「かさ高い荷物」; 「大（おお）」 is a prefix.
• Related天文学的てんもんがくてきNeutralFigurative for astronomical figures; 「大（おお）」 is a prefix, as in 「大赤字」.
• Antonym細ささWrittenWritten-style prefix meaning small or fine, the size opposite of 「大（おお）」.

Use the prefix 「大（おお）」 for big or serious things, as in 「大雨」「大物」; the plain adjective is 「大きい」. Pick 「大規模」 for large scale, 「莫大」 for huge sums, 「絶大」 for enormous influence; the opposite prefixes are 「細（ささ）」 and 「小」.

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

1. （おお）程度ていど・体形たいけい・器量きりょうが大おおきい。