someone who is lazy, doesn't work much, doesn't have much knowledge of the society and can be weak
köken: công tử (“mandarin's son”) + bột (“flour”), literally “a son of a mandarin [as white and soft as] flour.” bột may also come from French poste (theorizing that công tử bột meant the son of a colonial post office worker who is rich), or from the two names of Hoa Bột, Ba Bột (later thằng Bột) used in hát tuồng to refer to sons of mandarins.
köken: ཕྱལ (phyal, “flat”) + nominalisation suffix པ (pa). The sense is that the flatness is the terrain of their view as well as their conduct, they neither seek to rise through merit, nor fear falling into non-human lives and hells through unmeritorious activity.