The word "gauntleting" refers to the act of subjecting someone to a challenging or difficult test or trial. There are several synonyms for this word, each with its own nuance. One alternative is the term "trial by fire," which has a connotation of testing someone's fortitude or loyalty under intense pressure. Another synonym is "ordeal," which suggests a difficult or painful experience that must be endured to prove oneself. Additionally, "testing one's mettle" suggests a challenge that proves one's strength of character. "Baptism of fire" is another synonym that refers to a difficult and challenging initiation or introduction to a new experience.