moonbeam

noun4

1. •
   A ray or shaft of moonlight.

   • A moonbeam pierced the heavy cloud! — 1850
2. •
   Someone who tends to be dreamy and prone to unrealistic romanticism.

   • Dreaming of the mountain was for moonbeams, he told me, not for people who had been born up there. — 2011
3. •
   A goal or aspiration that appears attractive but is ultimately insubstantial.

   • So much for moonbeams and politics. — 1968
4. •
   Any of various Australasian lycaenid butterflies of the genus Philiris.