False gods, surprisingly solid (5)
I believe the answer is:
idols
'false gods' is the definition.
(I've seen this before)
'surprisingly solid' is the wordplay.
'surprisingly' indicates an anagram (a surprising ordering of the letters).
'solid' is an anagram of 'IDOLS'.
(Other definitions for idols that I've seen before include "Effigies worshipped as gods" , "Solid (anag.)" , "Solid kind of images" , "Graven images sometimes worshipped" , "Much-admired persons" .)