Is it permissible to tuck a short shirt into trousers, and is that considered imitation of disbelievers? Does the ruling differ when wearing a long jacket or a suit jacket? And what are the scholars' opinions regarding wearing shirts and trousers, praying in them, and the appropriate manner of wearing them?

The criterion for imitating disbelievers is to perform actions specific to them. Therefore, any clothing that is exclusive to them is impermissible for a Muslim to wear. However, what has become widespread among Muslims and is no longer distinctive to disbelievers is not considered imitation when worn, such as tucking a shirt into trousers, even if it was previously their attire, because the meaning that makes it imitation has vanished. Consequently, there is no harm in tucking a shirt into trousers if it is modest and does not define the awrah (private parts).