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Treason in Irish (Tréas): Meaning, Pronunciation, Usage

‘tréas’ also means: disloyalty

The Irish for treason is tréas, a masculine noun.
Updated October 2026Report a mistake

How to say “treason” in Irish

Irish:
tréas
English:
treason, disloyalty
Word type:
noun
Gender:
masculine, third declension
Pronunciation:
“tray-uss”  /tʲɾʲeːsˠ/
Various forms
Genitive singular:
tréasa, an tréasa (e.g. cúiseamh tréasa, a charge of treason)

What does “tréas” mean?

“Tréas” has two alternative meanings. The most common comes first.

treason
The crime of betraying your country or ruler, for example by helping its enemies or trying to overthrow the state.Also: high treason, betrayal of country.
1 other meaning: disloyalty
2disloyalty
Betrayal of trust or loyalty towards a person, cause or group.Also: betrayal, treachery, rebellion.

“Tréas” with the article

Here is tréas after the article (an t-alt).

an tréas
the treason
No change after an

“Tréas” in a sentence: Irish examples

Common Irish sentences using tréas, the Irish word for treason.

Cuireadh tréas ina leith.
He was accused of treason.
Ciontaíodh í i dtréas in aghaidh an stáit.
She was convicted of treason against the state.
Ba é an pionós báis a bhí ar thréas fadó.
Long ago treason was punishable by death.
Crochadh na ceannairceoirí as tréas.
The rebels were hanged for treason.
Tá an dlí tréasa an-sean.
The law of treason is very old.
Mheas an rí gur tréas a bhí ann.
The king considered it treason.
Seasadh cúirt i gcás tréasa an tseachtain seo.
A court sat in a treason case this week.

Other nouns in Irish

More everyday Irish nouns to learn next.

Treason in Irish: frequently asked questions

What is the Irish for treason?

The Irish for treason is tréas (pronounced “tray-uss”). It’s a masculine noun. Depending on context it can also mean disloyalty.

How do you pronounce tréas in Irish?

Tréas is said like “tray-uss” (IPA /tʲɾʲeːsˠ/).

Does tréas have a plural?

No plural form is given for tréas in the standard. Many abstract and mass nouns in Irish have no plural.

Does tréas have more than one meaning?

Yes. Tréas can mean treason or disloyalty, depending on context; the first is the most common.

Why does tréas change to thréas or dtréas?

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

What is the difference between 'tréas' and 'feall'?

'Tréas' is mainly the legal crime of treason against the state, while 'feall' is betrayal or treachery in general, as in 'feall ar charaid'.

What do you call a person who commits treason?

A traitor is usually 'fealltóir' or 'tréatúir'.

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