Does 髭 refer to the beard or the moustache? My dictionary lists `` as **moustache / beard** , but from the example sentences in WWWJDIC, it seems like `` is more often used to mean "beard" than "moustache" ? So for example, in this sentence: ``, is it clear to the listener that the speaker wanted to say "He grew a _beard_ to look more mature", and not "He grew _mustache_ to look more mature"? Or is it ambiguous and it could mean either one?

Your example says he grew facial hair. If it's a Japanese person, I would even dare say that it unambiguously refers to a beard, since I haven't seen many moustaches recently in Japan (beside mines), while I keep seeing guys struggling to get a beard :)

The unambiguous words you can use are:

* chin beard
* moustache
* moustache
* goatee
* sideburns
* whiskers