to peep (through); to peek; to await (one's chance); to guess; to infer
to perceive; to understand
to watch for an unguarded moment
to wait for an opportunity
to sound out a person's feelings; (lit.) to consult a person's pleasure
to make sure someone is asleep; to listen for the breath of a sleeping person; to commit a wrongdoing while someone is sleeping
to make a personal judgment on a problem with little insight; (lit.) to look at the sky through a tube (Zhuangzi)