一竅不通

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

one / single / a (article) / as soon as / entire; whole; all; throughout / "one" radical in Chinese characters (Kangxi radical 1) / also pr. [yao1] for greater clarity when spelling out numbers digit by digit

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

no; not so / (bound form) not; un-

to be obstructed / to be blocked up / to be impassable / to make no sense / to be illogical

to go through / to know well / (suffix) expert / to connect / to communicate / open / to clear / classifier for letters, telegrams, phone calls etc

classifier for an activity, taken in its entirety (tirade of abuse, stint of music playing, bout of drinking etc)