irregular, unusual, not normal
No creo que sea una frase irregular.
I don't think it's an irregular phrase.
Cuando se empieza a soñar, la respiración se vuelve irregular y menos profunda.
When you start dreaming, your breathing becomes irregular and more shallow.
The terrain was very uneven.
Comandante Chekov, esto es totalmente irregular.
Commander Chekov, this is completely irregular.
— Viaje a las estrellas II: La ira de Khan (1982)
El precio del tomate es muy irregular durante todo el año.
The price of tomatoes is very irregular throughout the year.
This is very irregular.