What is a synonym, in one line? It is a word or phrase that means the same, or almost the same, as another word in a particular sentence: big and large, quick and fast, begin and start. The term comes from Greek roots meaning "together" and "name", so a synonym is literally a word that shares a name for the same thing.
This page gives you the definition, the related adjective synonymous, the main kinds of synonyms, and the traps that catch writers who swap words too freely. Every word page on the site then applies these ideas to one headword.
Swatch at a glance
Short definition
A word with the same or nearly the same meaning as anotherPart of speech
Noun (plural: synonyms)Adjective
synonymous, as in "synonymous with"Pronunciation
SIN uh nimOpposite term
Classic pairs
big and large, happy and glad, end and finishWatch out
Very few pairs match in every sentence
What is a synonym? Definition and meaning
A simple synonym definition: a word that can replace another word in a sentence without changing what the sentence says. Most textbooks give a version of that line, and the published synonym definitions differ only in how strict they are. A synonyms definition in a school glossary is usually the loose one; a synonym defined by a linguist is usually the strict one. A strict view says true synonyms must match in every possible use, which almost never happens. A practical view, the one writers use, says two words are synonyms when they share a meaning in the context at hand.
So the meaning of synonym is really about overlap. Couch and sofa overlap almost completely. Bright and smart overlap only when you are talking about a person's mind, not a lamp.
What does synonymous mean?
The adjective synonymous describes words that are synonyms of each other: "Shut and close are synonymous." To define synonymous more broadly, it also means so closely linked that one suggests the other: "For many people, that town is synonymous with good cheese." In this second use it nearly always takes with. So the synonymous meaning has two layers: equal in sense, or tightly tied together in the minds of readers.
The noun for the relationship is synonymy, a term you will mostly meet in linguistics classes. In everyday writing, "these words are synonyms" is clearer.
Synonyms meaning and examples by type
Synonyms are not all alike. Sorting them by type helps you see which swaps are safe.
| Type | What it means | Example pair |
|---|---|---|
| Near-total | Swap almost anywhere | couch, sofa |
| Strength | Same idea, more or less force | warm, hot, scorching |
| Formality | Same idea, different setting | kids, children |
| Attitude | Same idea, different judgment | thrifty, stingy |
| Regional | Same thing, different country | apartment, flat |
| Sense-based | Match in one meaning only | bright, clever |
The attitude type matters most. Confident and arrogant both describe someone sure of themselves, but one is a compliment. See the confident page for more on that line.
Example synonym swaps in real sentences
- The test was hard becomes the test was difficult. See difficult.
- We need to fix the leak becomes we need to repair the leak.
- She was happy with her grade becomes she was pleased with her grade. See happy.
- The results show a pattern becomes the results reveal a pattern. See show.
- It is important to rest becomes it is essential to rest. See important.
- The room was big becomes the room was spacious.
A student essay line: "The author uses imagery to show sadness and uses color to show hope." Swapping the second verb gives "The author uses imagery to show sadness and color to suggest hope." The repeat disappears, and suggest hints that the hope is quieter.
Synonym and antonym side by side
A synonym shares meaning; an antonym reverses it. Learners often study the two together because each makes the other clearer.
| Word | Synonym | Antonym |
|---|---|---|
| brave | courageous | cowardly |
| ancient | very old | modern |
| generous | giving | stingy |
| accept | agree to | refuse |
The full guide on what an antonym is covers the different kinds of opposites.
Why perfect synonyms are rare
If two words meant exactly the same thing in every case, one would usually fall out of use. Languages keep both only when each earns a job. That job can be:
- Tone: pass away is gentler than die.
- Grammar: you can say "I am afraid of dogs" but not "an afraid dog"; you say "a frightened dog".
- Fixed pairs: we say heavy rain, not weighty rain, even though heavy and weighty can be close elsewhere.
- Field: doctors write cardiac, while everyone else says heart.
This is why each word page groups synonyms by sense and flags the formal, informal and old-fashioned ones.
Picking the closest match
Before you swap, read the sentence with the new word and ask three things. Does it keep the sense? Does it keep the strength? Would the reader expect it in this setting? If any answer is no, try the next option in the list. The hubs for essay and academic words and feelings and emotions give tailored tips, and the synonym finder on the home page takes you straight to any word.
Frequently asked questions
What's a synonym in simple words?
A word that means the same as another word. Little is a synonym of small, and shout is a synonym of yell.
What does synonym mean in a sentence?
You use it to say two words share a meaning: "Glad is a synonym for happy." Both of and for are fine after it.
How do you define synonym for a child?
Say it is a different word that means the same thing, then give pairs they know: big and huge, cold and chilly, sleepy and tired.
What is the plural of synonym?
Synonyms. The adjective is synonymous and the abstract noun is synonymy.
Can a phrase be a synonym?
Yes. Put off is a synonym for postpone, and a lot is a synonym for many. Phrases and single words can stand in for each other.
Is a synonym always better than repeating a word?
No. Repeating a key term can make a point clearer, especially in technical writing. Swap when the repeat sounds clumsy, not just because it is a repeat.