赤・紅・朱・緋|あかaka[1]atamadaka (head-high)

1. no-adjectivered; crimson; scarlet
   信号機しんごうきが赤あかの間あいだは道路どうろを渡わたるな。↗

   Don't cross the road when the signal is red.
2. nounred-containing colour (e.g. brown, pink, orange)
3. nounRed (i.e. communist)often written as アカ
   サダムが脅威きょういでないなどと言いうのは、赤あかがかった反戦はんせん運動うんどうの人ひと達たちくらい。↗

   It's only the anti-war pinkos who say things like Saddam isn't a threat.
4. nounred light (traffic)
5. nounred ink (i.e. in finance or proof-reading); (in) the red
6. no-adjectivecomplete; total; perfect; obvious
7. nouncopper
8. noun, hanafudared 5-point card

• Synonym赤色あかいろNeutralThe plain colour name for red, more objective than 「赤」. Read 「せきしょく」, it can mean the colour itself (「赤色光」) or communism and left-wing politics.
• SynonymレッドNeutralLoanword used mostly in compounds and colour names like 「レッドカード」 and 「ワインレッド」; it rarely stands alone.
• Synonym朱あけWrittenOld written word for vermilion red with an elegant feel, as in 「朱に染まる」; not used in everyday speech.
• Synonym丹色にいろWrittenWritten, archaic colour name for a deep, orange-tinged red like vermilion, seen at shrines and in classics; in daily speech say 「赤」.
• Synonym緋ひWrittenWritten word for an extremely vivid, intense deep red, as in 「緋色」; strongly literary — in everyday speech say 「真っ赤」.
• Related赤みあかみNeutralA reddish tinge or slight redness, as in 「顔に赤みが差す」; it concerns how red something is, while 「赤」 names the colour itself.

Default to 「赤」 for red in everyday use. Use 「赤色」 to name the colour objectively and 「赤み」 for a reddish tinge; 「レッド」 appears in compounds. 「丹色」, 「朱」 and 「緋」 are written colour names for specific deep reds.

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

1. あか。出血しゅっけつしたばかりの血ちの色いろ。