unbecoming

"Her unbecoming attire drew disapproving looks from the guests."

"He realized that his behavior at the party was unbecoming of a gentleman."

"The harsh words she used were unbecoming of someone in her position."

"The constant bickering between them began to unbecoming their friendship."

"His rude remarks could unbecoming to his reputation if he doesn't control them."

"She felt that her recent decisions were unbecoming to her ideals."