Meaning of 白 in words for "nonsense"? There are a number of Chinese words containing the 白 character that all mean &quot;nonsense&quot; or &quot;speaking nonsense&quot;:

白呼
夸白
白话

What's the significance of 白 in these words? 白 usually means &quot;white&quot;, &quot;clear&quot; or &quot;plain&quot;, so how did it become associated with nonsense? And is this related at all with the word 扯淡, which also means nonsense but originally meant 淡化 (water down)?
One of the meanings of 白 is, roughly "in vain":


  没有成就的，没有效果的：～忙。～说


I think it's easier to imagine how white/plain become "without effect" than it is to imagine how it became "nonsense".

P.S. 白话 means "plain speech" = vernacular, as far as i know.