窍

hole / opening / orifice (of the human body) / (fig.) key (to the solution of a problem)

opportunely / coincidentally / as it happens / skillful / timely

cave / cavity / hole / acupuncture point / Taiwan pr. [xue4]

secret / trick / knack / key

lit. doesn't (even) enter a single aperture (of one's head) / I don't understand a word (idiom) / it's all Greek to me

a trick / an ingenious method / know-how / the knack (of doing sth)

to get it straight / to start to understand things properly / enlightenment dawns

to be obsessed / to be possessed

mad about money (idiom)

the seven apertures of the human head: 2 eyes, 2 ears, 2 nostrils, 1 mouth

the mind / capacity for clear thinking

lit. spouting smoke through the seven orifices (idiom) / fig. to seethe with anger

a trick / an ingenious method / know-how / the knack (of doing sth)

nine orifices of the human body (eyes, nostrils, ears, mouth, urethra, anus)

out-of-body experience

unable to understand / can't get the point