In English, comparatives almost always end in the suffix ‘-er’, e.g. bigger, smaller, taller, older. Thankfully, Irish has a system that’s not that difficult to learn. Instead of adding a suffix after the word, you simply add a short word before the adjective, níos. It’s just a particle that’s part of the comparative construction. Ultimately, it’s ní + is (a thing that is), which is the origin, but it’s not understood that way nowadays.
If you want to use the superlative, you simply use is before the adjective.
EXTRA: You can read about the copula is here. The copula need not come at the beginning of the sentence, and it is indeed embedded in ‘níos’ (and is the ‘is’ we see in superlatives). When the superlative is meant, it will be just before the adjective, e.g. is deise (best).
Níos is still understood as ní + is by stronger speakers, while this is falling out of use among younger speakers, it’s definitely still around.
Making the comparative and superlative often involves making the end of the adjective slender by placing an ‘i’ after the last vowel if that vowel is a, o or u, and adding an -e to the end of the adjective.
| ciúin | níos ciúine |
| greannmhar | níos greannmhaire |
If the adjective ends in a vowel, the particle níos is applied and no change occurs to the adjective
| crua | níos crua |
| buí | níos buí |
But of course, there are other irregulars. The adjective te/hot, for example, becomes níos teo/hotter, and the adjective breá/nice becomes níos breátha/nicer.
If the adjective ends in –ach, then the –ach is replaced with –aí. Similarly, adjectives ending in –each will be replaced by –í:
| aisteach | níos aistí |
| feiliúnach | níos feiliúnaí |
If the adjective ends in -úil, this ending is replaced by -úla:
| spórtúil | níos spórtúla |
| flaithiúil | níos flaithiúla |
If an adjective ends in -air, the ending is replaced with -ra:
| deacair | níos deacra |
| socair | níos socra |
Some more common examples are below:
| Adjective | Comparative | Superlative |
| mór (big) | níos mó (bigger) | is mó (biggest) |
| deas (good) | níos deise (better) | is deise (best) |
| olc (bad) | níos measa (worse) | is measa (worst) |
| beag (small) | níos lú (smaller) | is lú (smallest) |
| ard (tall) | níos airde (taller) | is airde (tallest) |
| álainn (beautiful) | níos áille (more beautiful) | is áille (most beautiful) |
| sean (old) | níos sine (older) | is sine (oldest) |
| óg (young) | níos óige (younger) | is óige (youngest) |
| mall (slow) | níos moille (slower) | is moille (slowest) |
| tapa (fast) | is tapa (faster) | is tapa (fastest) |
How to say something is more ____ than the other?
The word for ‘than’ in Irish is ná. Below are some examples of ná at play:
| bhí sí bliain níos sine ná mé | she was a year older than me |
| tá sé níos mó ná sin | it’s bigger than that |
| tá sé níos faide ó thuaidh ná mar is iondúil | it’s further north than usual |
| tá sé níos measa ná mar a bhí riamh | it’s worse than ever |
| is fearr léi dearg ná gorm | she likes red more than blue |
Image by Mediamodifier from Pixabay

I have learned so much reading your blog. Míle buíochas!!
Pretty sure it is the copula? Like Reuben is ainm dhom. It doesn’t have to go at the front. Is fearr é = it is better. An duine is fearr = the person who is the better (than everyone else).
Hello Reuben, thank you for your messages. Yes, will make adjustments to inlude: “The copula need not come at the beginning of the sentence, and it is indeed embedded in ‘níos’ (and is the ‘is’ we see in superlatives)”.