Thief or thieves?
Thief is singular. Thieves is the plural of thief. To understand why the singular noun, thief, modifies to thieves as a plural noun, keep reading.
The thieves escaped before the police arrived.
We’re as thick as thieves.
The two thiefs escaped before the police arrived.
Some thief steal small things.
Understanding the meaning and plural of thief
The history and meaning of the word ‘Thief’
The online dictionary defines a thief as “a person who steals, especially secretly or without open force; one guilty of theft or larceny.”
Which is correct, thieves or thiefs?
The plural of thief (thieves), is irregular. Though it ends in the regular –es as a plural noun, it does so by replacing its ending in the singular case. Nouns normally add on the -es/-s to showcase plurality: books, phones, dogs and cats all add an s to demonstrate more than one of something. It’s an easy and straightforward way to form a plural noun: just add an s to the singular noun.
This does not work with words such as thief, wolf, shelf, knife, (the list goes on.) It could have something to do with the fact that each of these words came to Modern English from the Germanic languages, or PIE (Proto-Indo-European languages.) The same rule that applies with these other Germanic derived nouns, (wolf, knife, wife, life, etc.) each ends in –ves as a plural noun, replacing the the sibilant -f/-fe in the singular case. See the chart below.
Nouns that end in -f/-fe and –ves
| Singular | Plural |
|---|---|
| dwarf | dwarves |
| elf | elves |
| cliff | cliffs |
| thief | thieves (or thiefs) |
| roof | roofs |
| hoof | hooves (or hoofs) |
As a rule of thumb, nouns that end in -f usually switch to -ves as a plural. Keep in mind, this isn’t always the case, like with ‘roof’, which only adds an -s.
Examples of thief and thieves in sentences
| Sentence examples: thief | Sentence examples: thieves |
| A petty thief is someone who has a record of small thefts. | We hang the petty thieves and appoint the great ones to public office. (Aesop) |
| There is no shortage of ways to be a thief, and many of them have a specific name. | Before they cleaned themselves up, they were thieves, thugs, and junkies. |
| A pickpocket is a thief who steals things, such as wallets or watches, directly from peopleās pockets or from their body. | Some thieves steal small things. |
| A burglar is a thief who breaks into or otherwise unlawfully enters a home or business to steal valuables. | Some thieves steal valuable items. |
| Set a thief to catch a thief. (Sunday Times, 2014) | Art and car thieves are common characters in pop culture. |
Origin of the word
From etymonline on thief:
Old English Ć¾eof “thief, robber,” from Proto-Germanic *theuba- (source also of Old Frisian thiaf, Old Saxon thiof, Middle Dutch and Dutch dief, Old High German diob, German dieb, Old Norse Ć¾iofr, Gothic Ć¾iufs).
Practice: Forms of “Thief”
The police arrested the ______ who had been robbing houses in the area.
A single ______ was caught on the security camera.
The museum was on high alert for art ______.
He is an identity ______, so be careful with your personal information.
The two ______ escaped before the police arrived.
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FAQs
Q: What’s the plural of “thief”?
A: “Thieves” is the plural of “thief”. It’s noted as irregular because it replaces the singular’s ending (-f) with -ves before adding -es, unlike regular nouns.
Q: Is the word thief singular or plural?
A: Thief is singular. The plural, which represents more than one thief, is “thieves.”
Q: Why is thief plural “thieves”?
A: Unlike regular nouns adding -s/-es, “thieves” is irregular. It replaces the singular -f ending with -ves, a pattern shared by words like wolf and knife.
Q: Other words like thief use -ves?
A: Words like wolf, shelf, knife, wife, and life follow the same pattern as thief, changing their singular ending (-f or -fe) to -ves in the plural form.
Q: How is “thief” used in a sentence?
A: “A petty thief is someone who has a record of small thefts” and “A burglar is a thief who breaks into or otherwise unlawfully enters a home or business.”
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Citation: Yash, D. “How to Use Thief Plural (Explained, Examples & Worksheet)” Grammarflex. www.grammarflex.com/thief-plural/
Yash, D. "How to Use Thief Plural (Explained, Examples & Worksheet)." Grammarflex, Aug 24, 2025, https://grammarflex.com/thief-plural/.
