المعنى الاصطلاحي :

Contravention of performing an action to Islamic law and not attaining its legal implications.

الشرح المختصر :

"Fasaad" (defect/corruption) is a description given to a statement or action that is done in a way that does not conform to Islamic law because of the absence of one of the conditions or pillars of that statement or action, or because of the presence of an impediment. "Fasaad" may take place in an act of worship, such as prayer and fasting, or in transactions, such as selling and hiring. For example, the prayer is considered as "faasid" (void) if one of its conditions is missing, such as "tahaarah" (purification), or due to the presence of an impediment to prayer, such as menses. A transaction is considered as "faasid" if the condition of mutual consent is not met or if there is an impediment to the transaction, such as the case of a child's sale. The legal implications are the end results for which the transaction was conducted or the act of worship was performed. The implications of a sale transaction are the transfer of ownership and taking the goods into possession, and the implications of prayer are the attainment of reward and the fulfillment of the religious obligation.

التعريف اللغوي المختصر :

"Fasaad": damage or defect in something. Opposite: "salaah" (soundness) and "sihhah" (validity). Original meaning: distancing from a moderate state.