通畅

通畅	tōng chàng	unobstructed; clear / (of writing or thinking) coherent; fluent
通	tōng	to go through / to know well / (suffix) expert / to connect / to communicate / open / to clear / classifier for letters, telegrams, phone calls etc
通	tòng	classifier for an activity, taken in its entirety (tirade of abuse, stint of music playing, bout of drinking etc)
畅	chàng	free / unimpeded / smooth / at ease / free from worry / fluent