General annoyances:
* Molesto/a: This is a very common word for "annoying" and can be used in most situations.
* Irritante: This word implies something that causes irritation or annoyance.
* Fastidioso/a: This word suggests something that is tedious or bothersome.
* Pesado/a: This word means "heavy" but can also be used to describe someone who is annoyingly persistent or demanding.
Specific annoyances:
* Cansado/a: This means "tired," but can also be used to express being annoyed or bored.
* Aburrido/a: This means "bored," but can also be used to describe something that is tedious or uninteresting.
* Estúpido/a: This means "stupid," but can also be used to express annoyance or frustration.
* Insoportable: This means "unbearable" and is used to describe something that is extremely annoying.
Informal/colloquial:
* Un rollo: This literally means "a roll," but can be used to describe something that is annoying or bothersome.
* Un coñazo: This is a very informal word for "a pain in the neck" and can be used to describe something that is annoying or tedious.
* Una lata: This literally means "a can," but can be used to describe something that is annoying or troublesome.
The best word to use will depend on the context and the level of formality.
For example, you might say "El ruido de la construcción es muy molesto" (The noise from the construction is very annoying) or "Mi hermano es un rollo cuando está de mal humor" (My brother is a pain in the neck when he's in a bad mood).