sinus (pouch or cavity in any organ or tissue)

(medicine) sinus

a headache (pain or ache in the head)

sinusitis

be blocked, be clogged / be packed, completely filled / shorten, become shorter / be unable to do (something) well, be stuck / arrive at one’s destination, be at the end

boring / trivial, insignificant,useless / absurd, foolish, silly

nasal cavity

nasal cavity - a large air-filled space above and behind the nose in the middle of the face.

(chiefly women's speech) first person singular pronoun: I, me

assistant, sub-, vice-, auxiliary, supplemental