通畅

unobstructed / clear

unobstructed; clear / (of writing or thinking) coherent; fluent

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)

free / unimpeded / smooth / at ease / free from worry / fluent