What Is Another Word For Not Proper?

What Is Another Word For Not Proper? Improper, indecent, unbecoming, unseemly are applied to that which is unfitting or not in accordance with propriety. What word can replace proper? Some common synonyms of proper are appropriate, apt, felicitous, fitting, fit, happy, meet, and suitable. What’s a word for not proper? not good enoughunsuitable flimsy futile