soap bubble

• soap-bubble

 

soap bubble (plural soap bubbles)

1. A very thin film of soapy water that forms a sphere with an iridescent surface.
2. (figurative) Anything attractive but insubstantial.
   • 1879, John Campbell Shairp, Robert Burns, London: Macmillan:

     These words so pierce this soap-bubble of the metaphysicians, that we can hardly read them without fancying that the poet meant them to be ironical.

• soap film