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Betrayer in Irish (Brathadóir): Meaning, Pronunciation, Usage

‘brathadóir’ also means: detector · index finger

The Irish for betrayer is brathadóir, a masculine noun (plural brathadóirí).
Updated October 2026Report a mistake

How to say “betrayer” in Irish

Irish:
brathadóir
English:
betrayer, detector, index finger
Word type:
noun
Gender:
masculine, third declension
Pronunciation:
“BRAH-uh-doh-ir”  /ˈbɾˠahəd̪ˠoːɾʲ/
Various forms
Plural:
brathadóirí (betrayers)
Genitive singular:
brathadóra, an bhrathadóra (e.g. ainm an bhrathadóra, the betrayer's name)
Genitive plural:
brathadóirí, na mbrathadóirí (e.g. scéalta na mbrathadóirí, the stories of the betrayers)

What does “brathadóir” mean?

“Brathadóir” has three alternative meanings. The most common comes first.

betrayer
A person who betrays someone, especially by informing on them.Also: informer, traitor, spy.
2 other meanings: detector or index finger
2detector
A device that detects something, such as smoke, gas or metal.Also: sensor, alarm.
3index finger
The finger next to the thumb, used for pointing.Also: forefinger, pointing finger.

Other Irish words for betrayer: fealltóir (traitor)

“Brathadóir” with the article

The plural of betrayer in Irish is brathadóirí. Here is brathadóir after the article (an t-alt), in the singular and the plural.

an brathadóir
the betrayer
No change after an
na brathadóirí
the betrayers
Plural: no change after na

“Brathadóir” in a sentence: Irish examples

Common Irish sentences using brathadóir, the Irish word for betrayer.

Tá brathadóir deataigh sa chistin.
There's a smoke detector in the kitchen.
Bhí an brathadóir deataigh ag bípeáil ar maidin.
The smoke detector was beeping this morning.
Caithfidh mé ceallra an bhrathadóra a athrú.
I have to change the detector's battery.
Cheannaíomar dhá bhrathadóir nua inné.
We bought two new detectors yesterday.
Níl mo bhrathadóir miotail ag obair.
My metal detector isn't working.
Ní raibh muinín acu as na brathadóirí.
They had no trust in the informers.
Tugadh brathadóir air i measc a mhuintire féin.
He was called a traitor among his own people.

Other nouns in Irish

More everyday Irish nouns to learn next.

Betrayer in Irish: frequently asked questions

What is the Irish for betrayer?

The Irish for betrayer is brathadóir (pronounced “BRAH-uh-doh-ir”). It’s a masculine noun and the plural is brathadóirí. Depending on context it can also mean detector or index finger.

How do you pronounce brathadóir in Irish?

Brathadóir is said like “BRAH-uh-doh-ir” (IPA /ˈbɾˠahəd̪ˠoːɾʲ/).

What is the plural of betrayer in Irish?

The plural of brathadóir is brathadóirí; with the article, na brathadóirí means “the betrayers”. The genitive plural is brathadóirí, as in scéalta na mbrathadóirí (the stories of the betrayers).

Does brathadóir have more than one meaning?

Yes. Brathadóir can mean betrayer, detector or index finger, depending on context; the first is the most common.

Why does brathadóir change to bhrathadóir or mbrathadóir?

Irish changes the start of some words after certain words. After mo (my) brathadóir becomes mo bhrathadóir (lenition), and after ár (our) or i (in) it becomes ár mbrathadóir (eclipsis).

Is 'brathadóir' the same as 'braiteoir'?

Both can mean detector or sensor; 'braiteoir' is the usual technical term for a sensor, while 'brathadóir' is common in phrases like 'brathadóir deataigh'.

Which word means traitor?

'Brathadóir' is a betrayer or informer; 'fealltóir' is the general word for a traitor.

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