HeyRua Get the app

Complexity in Irish (Castacht): Meaning, Pronunciation, Usage

‘castacht’ also means: complication

The Irish for complexity is castacht, a feminine noun (plural castachtaí).
Updated October 2026Report a mistake

How to say “complexity” in Irish

Irish:
castacht
English:
complexity, complication
Word type:
noun
Gender:
feminine, third declension
Pronunciation:
“KAS-tukht”  /ˈkasˠt̪ˠəxt̪ˠ/
Various forms
Plural:
castachtaí (complexities)
Genitive singular:
castachta, na castachta (e.g. leibhéal na castachta, the level of complexity)
Genitive plural:
castachtaí, na gcastachtaí (e.g. réiteach na gcastachtaí, the resolution of the complications)

What does “castacht” mean?

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

complexity
The quality of being complicated, intricate or involved.Also: intricacy, complication, complicatedness.
1 other meaning: complication
2complication
A complicated detail or point; something that makes a matter intricate.Also: intricacy, complexity.

“Castacht” with the article

The plural of complexity in Irish is castachtaí. Here is castacht after the article (an t-alt), in the singular and the plural.

an chastacht
the complexity
Lenition: c becomes ch after an (feminine noun)
na castachtaí
the complexities
Plural: no change after na

“Castacht” in a sentence: Irish examples

Common Irish sentences using castacht, the Irish word for complexity.

Níor thuig mé castacht na faidhbe.
I didn't understand the complexity of the problem.
Cuireann castacht na rialacha mearbhall orm.
The complexity of the rules confuses me.
Níl aon chastacht ag baint leis an obair.
The work isn't complicated at all.
Tá go leor castachtaí sa scéal seo.
There are lots of complications in this story.
Is mór an chastacht atá i gcóras na gcánacha.
The tax system is very complex.
Chuir castacht na foirme isteach orm.
The complexity of the form annoyed me.

Other nouns in Irish

More everyday Irish nouns to learn next.

Complexity in Irish: frequently asked questions

What is the Irish for complexity?

The Irish for complexity is castacht (pronounced “KAS-tukht”). It’s a feminine noun and the plural is castachtaí. Depending on context it can also mean complication.

How do you pronounce castacht in Irish?

Castacht is said like “KAS-tukht” (IPA /ˈkasˠt̪ˠəxt̪ˠ/).

What is the plural of complexity in Irish?

The plural of castacht is castachtaí; with the article, na castachtaí means “the complexities”. The genitive plural is castachtaí, as in réiteach na gcastachtaí (the resolution of the complications).

Does castacht have more than one meaning?

Yes. Castacht can mean complexity or complication, depending on context; the first is the most common.

Why does castacht change to chastacht or gcastacht?

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

What is the opposite of castacht?

The opposite is simplíocht, simplicity; the noun castacht comes from the adjective casta, complicated.

Learn Irish by
actually speaking it

Learn everyday Irish words like castacht through guided conversation with Rua.

7-day free trial. Cancel anytime.

The HeyRua app home screen