赤子・赤児|あかごakago[0]heiban (flat)

1. nounbaby; infant

• Synonym赤ん坊あかんぼうNeutralNeutral everyday word for a baby, stressing a child only recently born; more colloquial than 「赤子」 and the usual choice in speech.
• Synonym赤ちゃんあかちゃんCasualColloquial and affectionate way to say baby; the most common word for an infant in daily conversation.
• Synonym乳児にゅうじWrittenWritten term, mainly medical, for a nursing infant under about one year old.
• SynonymベビーCasualColloquial loanword for baby, used mostly as a prefix as in 「ベビーカー」.
• RelatedみどりごWrittenWritten term for a newborn baby, with a literary flavor; rare in everyday speech.
• Related乳飲み子ちのみごWrittenWritten term for a baby still at the breast; stresses that the child is still nursing.
• Antonym老人ろうじんNeutralNeutral word for an old person; the opposite end of the age scale from a newborn 「赤子」.

In daily conversation say 「赤ちゃん」 or 「赤ん坊」; 「乳児」 is the medical term. 「赤子」 itself is written-style and also appears in idioms like 「赤子の手をひねる」; 「ベビー」 serves as a prefix like 「ベビーカー」.

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

1. （せきし, あかご）乳児にゅうじ、赤ん坊あかんぼう。
2. （せきし 比喩ひゆ）人民じんみん。