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Illegal in Irish (mídhleathach): Meaning, Forms, Examples

The Irish for illegal is mídhleathach: gnó mídhleathach, an illegal business.
Updated October 2026Report a mistake

How to say “illegal” in Irish

Irish:
mídhleathach
English:
illegal
Word type:
adjective
More illegal:
níos mídhleathaí
Most illegal:
is mídhleathaí
Plural:
mídhleathacha
Pronunciation:
“MEE-yla-hukh”  /ˈmʲiːˌɣʲlʲahəx/

What does “mídhleathach” mean?

illegal
Not allowed by law.Also: unlawful, illicit, against the law.

Other Irish adjectives for illegal: coiriúil (criminal), neamhdhlíthiúil (illegal), neamhdhleathach (illegal)

“Mídhleathach” after a noun

An Irish adjective comes after its noun. Here is mídhleathach after gnó (business, masculine), after gníomhaíocht (activity, feminine) and after a plural.

after a masculine noungnó mídhleathachan illegal business
after a feminine noungníomhaíocht mhídhleathachan illegal activity
after a plural noungnóthaí mídhleathachaillegal businesses

séimhiú (the h) the ending

feminine
gníomhaíochtactivity
+
mídhleathachillegal
=
gníomhaíocht mhídhleathachan illegal activity

After a feminine noun the adjective gets a séimhiú, an h after its first letter: gníomhaíocht mhídhleathach. After a masculine noun it stays as it is: gnó mídhleathach.

plural
gnóthaíbusinesses
+
mídhleathachaillegal, plural
=
gnóthaí mídhleathachaillegal businesses

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

More illegal, most illegal, very illegal

níosmore
+
mídhleathaíillegal
=
níos mídhleathaímore illegal
ismost
+
mídhleathaíillegal
=
is mídhleathaímost illegal
more illegalníos mídhleathaíin the past tense: ní ba mhídhleathaí
most illegalis mídhleathaíin the past tense: ba mhídhleathaí
as illegal aschomh mídhleathach leno change after chomh
very illegalan-mhídhleathachan- lenites, except d, t and s
too illegalrómhídhleathachró- lenites

“Mídhleathach” in a sentence: Irish examples

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

Dúnadh an gnó mídhleathach sin anuraidh.
That illegal business was closed last year.
Gabhadh é as trádáil mhídhleathach.
He was arrested for illegal trading.
Fuair na gardaí drugaí mídhleathacha sa charr.
The guards found illegal drugs in the car.
Is cleachtas mídhleathach é seo in Éirinn.
This is an illegal practice in Ireland.
Tá sé mídhleathach tobac a chaitheamh anseo.
It is illegal to smoke here.

Other adjectives in Irish

More everyday Irish adjectives to learn next.

Illegal in Irish: frequently asked questions

What is the Irish for illegal?

The Irish for illegal is mídhleathach (pronounced “MEE-yla-hukh”). It comes after the noun: gnó mídhleathach, an illegal business; gníomhaíocht mhídhleathach, an illegal activity.

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

níos mídhleathaí is more illegal and is mídhleathaí is most illegal. In the past tense they become ní ba mhídhleathaí and ba mhídhleathaí.

Why does mídhleathach become mhídhleathach?

After a feminine singular noun an adjective is lenited: it gets an h after its first letter. So gníomhaíocht mhídhleathach (an illegal activity) but gnó mídhleathach (an illegal business), because gnó is masculine.

What is the plural of mídhleathach?

With a plural noun mídhleathach becomes mídhleathacha: gnóthaí mídhleathacha, gníomhaíochtaí mídhleathacha.

How do you say very illegal in Irish?

an-mhídhleathach. Too illegal is rómhídhleathach, and as illegal as is chomh mídhleathach le.

What is the opposite of 'mídhleathach'?

The opposite is 'dleathach' (legal, lawful). 'Neamhdhleathach' is also used with a similar meaning to 'mídhleathach'.

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