| 赤い | あかい | red; crimson; scarlet; vermilion | n5 |
| 赤 | あか | red; crimson; scarlet; red-containing colour (e.g. brown, pink, orange) | n5 |
| 真赤 | まっか | bright red; deep red; flushed (of face); downright (e.g. lie) | n1 |
| 赤ん坊 | あかんぼう | baby; infant | |
| 赤ちゃん | あかちゃん | baby; infant | n3 |
| 赤面 | せきめん | blushing; getting red in the face; embarrassment | n1 |
| 真っ赤 | まっか | bright red; deep red; flushed (of face); downright (e.g. lie) | n1 |
| 赤黒い | あかぐろい | dark red; dark brown; reddish brown | |
| 赤土 | あかつち | red clay; red earth; laterite; dark-red paint | |
| 赤色 | あかいろ | red; red color; communist; socialist | |
| 赤らめる | あからめる | to blush; to redden | |
| 赤子 | あかご | baby; infant | |
| 赤松 | あかまつ | Japanese red pine (Pinus densiflora); Japanese umbrella pine; tanyosho pine | |
| 赤裸々 | せきらら | naked; nude; unvarnished (e.g. truth); plain (e.g. fact) | |
| 赤裸 | あかはだか | stark naked; nude; bare; stripped of all belongings | |
| 赤坊 | アカボウ | Bodianus cylindriatus (species of hogfish) | |
| 赤銅 | しゃくどう | shakudo; gold-copper alloy, often with a blue patina | |
| 赤らむ | あからむ | to become red; to redden; to blush | |
| 赤ら顔 | あからがお | red face | |
| 赤み | あかみ | reddish tinge; tinge of red; slight redness; reddishness | |
| 赤旗 | あかはた | red flag; Red Flag (Communist Party newspaper) | |
| 赤字 | あかじ | (being in) the red; deficit; red letter; red writing | n1 |
| 赤十字 | せきじゅうじ | Red Cross | |
| 赤飯 | せきはん | red rice (beans and mochi) for auspicious occasions | |
| 赤毛 | あかげ | red hair; ginger hair | |
| 赤茶ける | あかちゃける | to turn reddish-brown; to turn rufous; to become discolored; to become discoloured | |
| 赤道 | せきどう | equator; (celestial) equator | |
| 赤地 | あかじ | red cloth; red background | n1 |
| 赤める | あかめる | to blush; to redden | |
| 赤帽 | あかぼう | red cap; (railway) porter; redcap | |
| 赤痢 | せきり | dysentery | |
| 赤蜻蛉 | あかとんぼ | (small) red dragonfly; darter (any dragonfly of genus Sympetrum, esp. the autumn darter, Sympetrum frequens); meadowhawk | |
| 赤心 | せきしん | sincerity; true heart; devotion | |
| 赤門 | あかもん | red gate (esp. at Tokyo University) | |
| 赤外線 | せきがいせん | infrared rays; infrared radiation | |
| 赤錆 | あかさび | red rust | |
| 赤とんぼ | あかとんぼ | (small) red dragonfly; darter (any dragonfly of genus Sympetrum, esp. the autumn darter, Sympetrum frequens); meadowhawk | |
| 赤絵 | あかえ | aka-e; late 19th century woodblock prints, using imported aniline dyes; red painting on ceramics | |
| 赤貧 | せきひん | extreme poverty | |
| 赤誠 | せきせい | sincerity; true heart; devotion | |
| 赤ワイン | あかワイン | red wine | |
| 赤紙 | あかがみ | draft papers; call-up notice; red paper | |
| 赤熱 | せきねつ | red heat | |
| 赤恥 | あかはじ | great shame (endured in the public eye); deep embarrassment; profound humiliation; utter disgrace | |
| 赤褐色 | せっかっしょく | reddish brown; rufous | |
| 赤木 | あかぎ | bishop wood (Bischofia javanica); barked tree; red tree | |
| 赤蛙 | あかがえる | any brown or reddish-brown frog of the family Ranidae; Japanese brown frog (Rana japonica) | |
| 赤化 | せっか | Sovietize; Sovietise; turning red; become communistic | |
| 赤貝 | あかがい | blood clam (Scapharca broughtonii); ark shell | |
| 赤鼻 | あかはな | red nose | |
| 赤軍 | せきぐん | Red Army (Soviet Union, 1918-1946); Workers' and Peasants' Red Army; Japanese Red Army; JRA | |
| 赤身 | あかみ | red flesh (of a fish); red-fleshed fish (e.g. tuna); lean meat; heartwood | |
| 赤手 | せきしゅ | bare handed | |
| 赤樫 | あかがし | Japanese evergreen oak (Quercus acuta) | |
| 赤みがかる | あかみがかる | to be tinged red | |
| 赤本 | あかほん | pulp fiction; dime novel; akahon; university entrance exam workbook (published by Kyōgakusha) | |
| 赤目 | あかめ | red eyes; bloodshot eyes; red-eye; red mullet (Chelon haematocheilus) | |
| 赤新聞 | あかしんぶん | scandal sheet; gutter press; yellow press | |
| 赤味噌 | あかみそ | dark-brown miso paste | |
| 腹赤 | ハラアカ | trout; Japanese dace (Tribolodon hakonensis); Nibe croaker (Nibea mitsukurii) | |
| 赤札 | あかふだ | red tag (esp. one attached to sold goods or discounted products); red label; swords (playing card suit in traditional Japanese gambling decks) | |
| 赤電車 | あかでんしゃ | last train (of the day) | |
| 赤肌 | あかはだ | grazed skin; abraded skin; bare surface of a mountain; nakedness | |
| 赤んぼう | あかんぼう | baby; infant | |
| まっ赤 | まっか | bright red; deep red; flushed (of face); downright (e.g. lie) | n1 |
| 赤切符 | あかぎっぷ | red traffic violation ticket (designating a serious violation); third-class ticket | |
| 赤血球 | せっけっきゅう | red blood cell; erythrocyte | |
| 赤むけ | あかむけ | scraped skin; graze; grazed skin | |
| 赤茄子 | あかなす | Chinese scarlet eggplant (Solanum integrifolium); tomato-fruit eggplant; tomato (Solanum lycopersicum) | |
| 赤金 | どう | copper (Cu); bronze (medal) | n5 |
| 赤鰯 | あかいわし | pickled sardines; dried sardines; red sardines; rusty and blunt sword | |
| 赤潮 | あかしお | red tide | |
| 赤腹 | あかはら | brown-headed thrush (Turdus chrysolaus); Japanese dace (Tribolodon hakonensis); Japanese fire belly newt (Cynops pyrrhogaster); dysentery | |
| 日赤 | にっせき | Japanese Red Cross Society (abbr); Nisseki | |
| 赤さび | あかさび | red rust | |
| 赤ずきん | あかずきん | Little Red Riding Hood | |
| 七赤 | しちせき | seventh of nine traditional astrological signs (corresponding to Venus and west) | |
| 赤膚 | あかはだ | grazed skin; abraded skin; bare surface of a mountain; nakedness | |
| 日本赤十字社 | にほんせきじゅうじしゃ | Japanese Red Cross Society; JRC | |
| 赤口 | しゃっこう | day that is unlucky except between the auspicious hours of 11am and 1pm (in the traditional calendar) | |
| 赤熊 | あかぐま | brown bear (esp. the Ussuri brown bear, Ursus arctos lasiotus) | |
| 赤玉 | あかだま | red ball; amber; jasper; patent medicine | |
| 赤砂糖 | あかざとう | brown sugar; unrefined brown sugar | |
| 赤道ギニア | せきどうギニア | Equatorial Guinea | |
| 赤線 | あかせん | red line; red-light district (marked by a red line on police maps); non-legal public road (denoted by a red line on cadastral maps; sometimes no longer physically existing) | |
| 赤ひげ | あかひげ | red beard; person with a red beard; Westerner; Ryukyu robin (Erithacus komadori) | |
| 赤剥け | あかむけ | scraped skin; graze; grazed skin | |
| 発赤 | ほっせき | rubefaction (reddening of the skin) | |
| 赤外 | せきがい | infrared | |
| 赤ゲット | あかゲット | red blanket; country bumpkin | |
| 赤児 | あかご | baby; infant | |
| 赤沈 | せきちん | erythrocyte sedimentation rate; ESR | |
| 赤血 | せっけつ | red blood | |
| 赤チン | あかチン | mercurochrome; merbromin solution | |
| 赤身魚 | あかみざかな | fish having red flesh (e.g. maguro, katsuo, saba, iwashi) | |
| 赤道祭 | せきどうさい | ceremony to celebrate crossing the equator | |
| 赤味 | あかみ | reddish tinge; tinge of red; slight redness; reddishness | |
| 赤燐 | せきりん | red phosphorus | |
| 赤花 | あかばな | willowherb (Epilobium pyrricholophum); safflower red; kimono color combination (crimson outside, bluish purple inside) | |
| 赤酢 | あかず | red vinegar made from fermented sake lees; plum vinegar with perilla leaves added | |