Elev og lærer
The appropriate antonym applicable for pupil is teacher.
l'enseignant!!
professeur
No they cant
To say "the teacher is friendly" in French, you would say "le professeur est sympathique."
the teacher chair is called 'la chaise du professeur' in French.
a music teacher is un / une professeur de musique in French.
l'enseignant(e) a....
mme.
"enseignante"
pupil
You can introduce an English teacher to a French teacher by saying, "Bonjour, this is [English teacher's name]. They teach English, and are interested in connecting with you to share teaching ideas and collaborate."