Definition of la-la:
(adj) :
Of indifferent quality; so-so.
(n) :
(slang, US) Something unusually good; (occasionally) something unusually bad.
(v) :
(intransitive) To sing or recite the syllable la repeatedly.
(v) :
(transitive) To sing (a song) with la replacing the song lyrics.
(n) :
(slang) A woman's genitals, especially the vagina; a sexually permissive woman.
(n) :
(Singapore, Malaysia) Alternative form of la la (“clams”). [(informal, Singapore, Malaysia) Venus clams (as food)]