| Word | Reading | Meaning | Level |
|---|
| 苦い | にがい | bitter | N5 |
| ご苦労様 | ごくろうさま | thank you for your hard work | N5 |
| 苦味 | にがみ | bitterness | N4 |
| 苦み | にがみ | bitter flavor | N4 |
| 苦労 | くろう | hardships, struggles | N4 |
| 苦難 | くなん | hardship | N3 |
| 苦情 | くじょう | complaint | N2 |
| 苦渋 | くじゅう | anguish, a bitter choice | N2 |
| 苦痛 | くつう | pain, distress | N2 |
| 苦心 | くしん | pains, effort | N2 |
| 苦境 | くきょう | predicament, plight | N2 |
| 労苦 | ろうく | toil | N2 |
| 苦渋の決断 | くじゅうのけつだん | agonizing decision | N1 |
| 苦衷 | くちゅう | internal distress, grief | N1 |
| 苦辛い | にがからい | delightfully bitter and pungent | N1 |
| 永年の労苦 | えいねんのろうく | multi-year toil and perseverance | N1 |
| 苦味の調和 | にがみのちょうわ | balanced harmony of natural plant alkaloids | N1 |
