If I share an incident that happened between me & my mother in law, what she told me and how I felt about it. Would that be backbiting? if I share about her beliefs and practices she follows that’s not mentioned in quran or hadees is that backbiting? And if I say someone I don’t like certain dish she prepares is that backbiting?
Generally speaking, this is backbiting.
But, if you tell about her ill treatment to someone to seek their genuine advice then this is not backbiting.
However, telling someone about her bad cooking and something similar comes under backbiting which is prohibited.