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Certain in Irish (deimhin): Meaning, Forms, Examples

The Irish for certain is deimhin: fear deimhin, a certain man.
Updated October 2026Report a mistake

How to say “certain” in Irish

Irish:
deimhin
English:
certain
Word type:
adjective
More certain:
níos deimhne
Most certain:
is deimhne
Plural:
deimhne
Pronunciation:
“DEV-in”  /dʲɪvʲənʲ/

What does “deimhin” mean?

certain
Known to be true without any doubt.Also: sure, definite, positive.

Other Irish adjectives for certain: áirithe (certain), cinnte (sure), dearfa (certain), siúráilte (sure)

“Deimhin” after a noun

An Irish adjective comes after its noun. Here is deimhin after fear (man, masculine), after tuairim (opinion, feminine) and after a plural.

after a masculine nounfear deimhina certain man
after a feminine nountuairim dheimhina certain opinion
after a plural nounfir dheimhnecertain men

séimhiú (the h) the ending

feminine
tuairimopinion
+
deimhincertain
=
tuairim dheimhina certain opinion

After a feminine noun the adjective gets a séimhiú, an h after its first letter: tuairim dheimhin. After a masculine noun it stays as it is: fear deimhin.

plural
firmen
+
deimhnecertain, plural
=
fir dheimhnecertain men

With a plural noun the adjective takes its plural form, deimhne. It also gets an h after a plural that ends in a slender consonant: fir dheimhne; after other plurals it does not: tuairimí deimhne.

More certain, most certain, very certain

níosmore
+
deimhnecertain
=
níos deimhnemore certain
ismost
+
deimhnecertain
=
is deimhnemost certain
more certainníos deimhnein the past tense: ní ba dheimhne
most certainis deimhnein the past tense: ba dheimhne
as certain aschomh deimhin leno change after chomh
very certainan-deimhinan- lenites, except d, t and s
too certainródheimhinró- lenites

“Deimhin” in a sentence: Irish examples

With a masculine noun, a feminine noun, a plural, a comparison and on its own.

Níl sé deimhin fós an dtiocfaidh sí.
It isn't certain yet whether she'll come.
Níl aon fhianaise dheimhin againn.
We have no definite evidence.
An bhfuil tú deimhin de sin?
Are you sure of that?
Is deimhin liom go bhfuil an ceart agat.
I'm sure you're right.
Is deimhin go dtiocfaidh sé amárach.
It is certain that he will come tomorrow.

Other adjectives in Irish

More everyday Irish adjectives to learn next.

Certain in Irish: frequently asked questions

What is the Irish for certain?

The Irish for certain is deimhin (pronounced “DEV-in”). It comes after the noun: fear deimhin, a certain man; tuairim dheimhin, a certain opinion.

How do you say more certain and most certain in Irish?

níos deimhne is more certain and is deimhne is most certain. In the past tense they become ní ba dheimhne and ba dheimhne.

Why does deimhin become dheimhin?

After a feminine singular noun an adjective is lenited: it gets an h after its first letter. So tuairim dheimhin (a certain opinion) but fear deimhin (a certain man), because fear is masculine.

What is the plural of deimhin?

With a plural noun deimhin becomes deimhne: fir dheimhne, tuairimí deimhne. After a plural that ends in a slender consonant it is lenited as well.

How do you say very certain in Irish?

an-deimhin. Too certain is ródheimhin, and as certain as is chomh deimhin le.

What is the difference between 'deimhin' and 'cinnte'?

Both mean certain, but 'cinnte' is far more common in speech, while 'deimhin' is more literary and appears in fixed phrases such as 'go deimhin' (indeed) and 'is deimhin liom' (I am sure).

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