信誓旦旦 Origin — Dong Chinese Dictionary

xìnshìdàndàn

vow

xìn trust

Conveys trusting (信) what a person (人) says (言). 人 is also a sound component.

Components

亻 Sound Meaning component

rén person

亻 is a component form of 人.

Change in sound

信 and 亻 don't sound similar in modern Mandarin due to historical phonetic changes. They were more similar in Old Chinese.
信 *s-ni[ŋ]-s
亻 *ni[ŋ]

言 Meaning component

yán speech

Character Evolution

Bronze form — Bronze Late Western Zhou ~800 BC

Bronze form — Bronze Mid Warring States ~300 BC

Bronze form — Bronze Late Warring States ~250 BC

Bronze form — Bronze Late Warring States ~250 BC

Bronze form — Bronze Late Warring States ~250 BC

Bronze form — Bronze Late Warring States ~250 BC

Bronze form — Bronze Late Warring States ~250 BC

Seal form — Seal Warring States (Chu) 475-221 BC

Seal form — Seal Warring States (Chu) 475-221 BC

Seal form — Seal Western Han 202 BC-9 AD

Seal form — Seal Shuowen ~100 AD

Seal form — Seal Shuowen ~100 AD

Seal form — Seal Shuowen ~100 AD

Clerical form — Clerical Qin 221-206 BC

Clerical form — Clerical Western Han 202 BC-9 AD

Clerical form — Clerical Western Han 202 BC-9 AD

Clerical form — Clerical Western Han 202 BC-9 AD

Clerical form — Clerical Eastern Han 25-220 AD

Regular Modern

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Historical Pronunciations

	Middle Chinese	Old Chinese	Gloss
Baxter-Sagart	sinH	s-ni[ŋ]-s	truthful

說文解字

《說文》：“信，誠也。从人，从言，會意。，古文从言省。訃，古文信。”

Sources

Character origin: 漢語多功能字庫
Readings & variants: Unicode
Historical pronunciations: Baxter-Sagart
Historical images: Academia Sinica
Etymology: Shuowen Jiezi (說文解字)

shì oath, vow

Phonosemantic compound. 言 represents the meaning and 折 represents the sound.

Components

言 Meaning component

yán speech

折 Sound component

zhé, zhē, shé break off

Change in sound

誓 and 折 don't sound similar in modern Mandarin due to historical phonetic changes. They were more similar in Old Chinese.
誓 *[d][a]t-s
折 *[d]ˤet-s

Character Evolution

Bronze form — Bronze Late Western Zhou ~800 BC

Bronze form — Bronze Late Western Zhou ~800 BC

Bronze form — Bronze Late Western Zhou ~800 BC

Bronze form — Bronze Late Spring and Autumn ~500 BC

Seal form — Seal Shuowen ~100 AD

Clerical form — Clerical Eastern Han 25-220 AD

Regular Modern

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Historical Pronunciations

	Middle Chinese	Old Chinese	Gloss
Baxter-Sagart	dzyejH	[d][a]t-s	swear

說文解字

《說文》：“誓，約束也。从言，折聲。”

Sources

Character origin: 漢語多功能字庫
Readings & variants: Unicode
Historical pronunciations: Baxter-Sagart
Historical images: Academia Sinica
Etymology: Shuowen Jiezi (說文解字)

dàn dawn

Depicts the sun (日) rising above the horizon (一) at dawn. In the oracle bone script the bottom component was the phonetic 丁, which was later reanalyzed as the earth or a horizon.

Components

日 Iconic component

rì sun

一 Iconic component

yī one

Depicts the horizon.

Character Evolution

Oracle form — Oracle Bone ~1250-1000 BC

Oracle form — Oracle Bone ~1250-1000 BC

Oracle form — Oracle Bone ~1250-1000 BC

Bronze form — Bronze Mid Western Zhou ~900 BC

Bronze form — Bronze Late Western Zhou ~800 BC

Bronze form — Bronze Late Western Zhou ~800 BC

Seal form — Seal Warring States (Chu) 475-221 BC

Seal form — Seal Warring States (Chu) 475-221 BC

Seal form — Seal Shuowen ~100 AD

Clerical form — Clerical Qin 221-206 BC

Clerical form — Clerical Eastern Han 25-220 AD

Clerical form — Clerical Eastern Han 25-220 AD

Regular Modern

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Component uses

Sound (4 of 12 verified)

但担坦胆袒靼疸妲笪怛钽亶

Meaning (3 of 4 verified)

Unknown (2 of 3 verified)

Historical Pronunciations

	Middle Chinese	Old Chinese	Gloss
Baxter-Sagart	tanH	tˤan-s	dawn

說文解字

《說文》：“旦，明也。从日見一上。一，地也。”

Sources

Character origin: 季旭昇《說文新證》p.539
Readings & variants: Unicode
Historical pronunciations: Baxter-Sagart
Historical images: Academia Sinica
Etymology: Shuowen Jiezi (說文解字)