The adjective "boring" is ennuyeux. So "you are boring" is Tu est ennuyeux (informal) or vous êtes ennuyeux(formal).
Because of the spelling, this would be the same for speaking to a man, woman, or multiple people.
The diffence between "you are boring" and "you are bored" in Spanish depends on which of the "to be" verbs is used.
If you use "ser", then you are suggesting an intrinsic characteristic. "Eres aburrido" is "you are boring".
If you use "estar", it is a transient. "Estás aburrido" is "you are bored".
aburrido
Facebook es aburrido
gente viejos aburridos
Los libros son aburridos
Translation: Este cuento es aburrido.
Translation: Es aburrido aquí.
Translation: Estoy aburrido.Note that if you use "ser" and say "soy aburrido" it means "I am a boring person."
boring = aburrido/a(s) (male/female(plural))
Translation: Hoy fue un día aburrido.
Era aburrido/a (masculine/feminine 'it') Pronounced 'AIRah ahbooRREEthaw/ah' ('th' as in 'the')
Translation: Hoy era aburrido.However, it is much more idiomatic to say, "Hoy me aburró." meaning "Today bored me."
Aburrido is boring. One thing to watch is the use of ser and estar with this. Estoy aburrido means "I am bored". Soy aburrido means "I am boring".