Adjectives

(s)face-to-facein each other's presence“a face-to-face encounter”

Adverbs

(r)face-to-face, face to facewithin each other's presence“she met the president face-to-face”
(r)face-to-face, face to face, oppositedirectly facing each other“the two photographs lay face-to-face on the table”, “lived all their lives in houses face-to-face across the street”, “they sat opposite at the table”