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Questioning in Irish (Ceistiú): Meaning, Pronunciation, Usage

‘ceistiú’ also means: querying

The Irish for questioning is ceistiú, a masculine noun. Ag ceistiú is questioning, from the verb ceistigh.
Updated October 2026Report a mistake

How to say “questioning” in Irish

Irish:
ceistiú
English:
questioning, querying
Word type:
noun (verbal noun)
Verbal noun of:
ceistigh, to question (ag ceistiú, questioning)
Gender:
masculine
Pronunciation:
“KESH-tyoo”  /ˈcɛʃtʲuː/
Various forms
Genitive singular:
ceistithe, an cheistithe (e.g. seomra ceistithe, interrogation room)

What does “ceistiú” mean?

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

questioning
The act of asking someone questions, especially formally or closely; verbal noun of the verb ceistigh.Also: interrogation, interrogating, quizzing.
1 other meaning: querying
2querying
The act of doubting or challenging something by raising questions about it; verbal noun of ceistigh.Also: questioning, challenging, doubting.

“Ceistiú” as a verbal noun

After ag, ceistiú means questioning: it is the verbal noun of the verb ceistigh (to question). A noun that follows it goes into the genitive.

agat
+
ceistiúverbal noun
=
ag ceistiúquestioning

“Ceistiú” with the article

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

an ceistiú
the questioning
No change after an

“Ceistiú” in a sentence: Irish examples

Common Irish sentences using ceistiú, the Irish word for questioning.

Bhí na gardaí ag ceistiú an fhir ar feadh uaire.
The guards were questioning the man for an hour.
Thosaigh an ceistiú go luath ar maidin.
The questioning began early in the morning.
Níor thaitin an ceistiú géar leis an bhfinné.
The witness did not like the sharp questioning.
Tugadh isteach chuig seomra ceistithe é.
He was brought into an interrogation room.
Bíonn an múinteoir i gcónaí ag ceistiú na ndaltaí.
The teacher is always quizzing the pupils.
Tá sé ag ceistiú an chinnidh sin anois.
He is questioning that decision now.
Mhair an ceistiú níos faide ná mar a cheap mé.
The questioning lasted longer than I thought.

Other nouns in Irish

More everyday Irish nouns to learn next.

Questioning in Irish: frequently asked questions

What is the Irish for questioning?

The Irish for questioning is ceistiú (pronounced “KESH-tyoo”). It’s a masculine noun. Depending on context it can also mean querying.

How do you pronounce ceistiú in Irish?

Ceistiú is said like “KESH-tyoo” (IPA /ˈcɛʃtʲuː/).

Does ceistiú have a plural?

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

Does ceistiú have more than one meaning?

Yes. Ceistiú can mean questioning or querying, depending on context; the first is the most common.

Why does ceistiú change to cheistiú or gceistiú?

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

What is the difference between ceistiú and ceistiúchán?

Ceistiú is the verbal noun, the act of questioning (ag ceistiú duine), while ceistiúchán usually means a formal interrogation or a questionnaire.

How do I say 'to question a decision'?

Use ceistigh with the object in the genitive after ag: tá sé ag ceistiú an chinnidh, he is questioning the decision.

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