• 非常ひじょう — emergency, extraordinary
• 非難ひなん — criticism, blame
• 非行ひこう — delinquency
• 非公式ひこうしき — unofficial
• 非公開ひこうかい — private, not open to public
• 非常識ひじょうしき — lack of common sense
• 非売品ひばいひん — not-for-sale item
• 非現実的ひげんじつてき — unrealistic

The kanji 非 originally depicts wings (⿰) turned away from each other — symbolizing opposition or wrongness. It has long been used to express negation or something incorrect.

In modern Japanese, 非 is frequently used as a prefix to indicate negation: 非常 (not normal), 非公式 (not official), and so on. It forms many abstract nouns with a sense of opposition or deviation.

彼かれの 発言はつげんは 非常識ひじょうしきです。
His remark is unreasonable.

この イベントは 非公式ひこうしきに 行おこなわれました。
This event was held unofficially.

The on-yomi "ヒ (hi)" is the standard reading and appears in nearly all uses of this character. It rarely appears alone and is most often used as a prefix indicating negation, such as in 非難 (criticism) or 非常 (emergency).