This is the 5203rd most frequent Arabic word.
بشيء
"بشيء" means "with something" in English.
Here, 'بشيء' is used to mean 'with something' indicating a need or involvement with an important matter.
أحتاج إلى مساعدتك بشيء مهم.
I need your help with something important.
In this sentence, 'بشيء' refers to 'the thing' specifying what the person is referring to.
هل انتهيت من العمل على بشيء الذي طلبته؟
Have you finished working on the thing I asked for?
Here, 'بشيء' implies 'of something' indicating an idea or concept under contemplation.