One synonym for "makes unwelcome" is "excludes," which means to intentionally keep someone or something out. Another word that fits is "alienates," which means to make someone feel isolated or estranged. "Shuns" is also a possible synonym, meaning to deliberately avoid or reject someone. "Repels" can be used to describe the act of driving someone away or causing them to feel uncomfortable. Other synonyms include "ostracizes," "snubs," and "disdain." Regardless of the word used, the result is the same: someone is made to feel unwelcome or unwanted.