Chinese Phrase - Good afternoon
Literal: Afternoon Good
Usually you'd go with 你好 (nǐhǎo), since that wouldn't cause any confusion. If a foreigner suddenly throws around with uncommon phrases, the native Chinese may not readily understand you. They may even pretend to understand what you said, even though they really thought you said some fancy English word.
Check out this group of Chinese phrases too. You might find more useful Mandarin phrases. The current Chinese phrase "Good afternoon" appears in this groupGreetings - Extended