Spiritually weak in JW terms = not doing much in FS, poor meeting attendance, Not blabbering like Oh Jah did this, Jah did that, isn't Jah wonderful…..
Reality is, the spiritually weak is sensing that all or something is fake in this religion.
When I was wakening, elders used to come and advise that I should be less materialistic and be more spiritual. I am the least materialistic but they had to blame it on me.