A synonym is a word that means the same, or nearly the same, as another word in the same language: 'big' and 'large', 'begin' and 'start', 'buy' and 'purchase'.

A synonym synonym（同義詞） is指 a word that means the same, or nearly the same, as another word in the same language在同一種語言裡跟另一個字意思相同或幾乎相同的字: 'big' and 'large', 'begin' and 'start', 'buy' and 'purchase'像'big'和'large'、'begin'和'start'、'buy'和'purchase'。

The honest truth your dictionary may not stress is that perfect synonyms barely exist. Two words that share a meaning almost always differ in something else — how formal they feel ('buy' at the shop, 'purchase' on a form), how strong they are ('slim' is kind, 'skinny' is not), what they combine with (a 'big mistake' sounds right, a 'large mistake' does not). So a synonym is a word you can often swap in, not always.

The honest truth your dictionary may not stress字典可能不會特別強調的真相 is是: that perfect synonyms barely exist完美的同義詞幾乎不存在。Two words that share a meaning兩個共享一個意思的字 almost always differ in something else幾乎一定會在別的地方不一樣 — how formal they feel正式程度不同 ('buy' at the shop, 'purchase' on a form'buy'用在商店，'purchase'用在表格上), how strong they are強度不同 ('slim' is kind, 'skinny' is not'slim'是友善的，'skinny'不是), what they combine with搭配的字不同 (a 'big mistake' sounds right, a 'large mistake' does not說'a big mistake'很順，'a large mistake'就怪怪的)。So所以 a synonym is a word you can often swap in同義詞常常可以互換, not always但不是每次都可以。

That is exactly why a thesaurus can get a student into trouble: it lists words that share a meaning, and says nothing about which one belongs in your sentence. The word is completely everyday in language classrooms.

That is exactly why a thesaurus can get a student into trouble這正是為什麼thesaurus（同義詞辭典）會害學生出包: it lists words that share a meaning它只列出意思相近的字, and says nothing about which one belongs in your sentence卻完全不告訴你哪一個才適合放進你的句子。The word is這個字 completely everyday in language classrooms在語言課堂上非常常見。

The adjective is 'synonymous', which in ordinary use has stretched past language — 'his name is synonymous with quality' means the two ideas bring each other to mind. The opposite is 'antonym'.

The adjective is形容詞是 'synonymous''synonymous', which in ordinary use has stretched past language在日常用法裡已經延伸到語言之外 — 'his name is synonymous with quality''his name is synonymous with quality' means意思是 the two ideas bring each other to mind這兩個概念會讓人聯想到彼此。The opposite is反義詞是 'antonym''antonym'。