Lois mad about key heroes (5)
I believe the answer is:
idols
'heroes' is the definition.
(I've seen this before)
'lois mad about key' is the wordplay.
'mad' indicates an anagram.
'about' means one lot of letters goes inside another.
'key' becomes 'd' (I've seen this in other clues).
'lois' with letters rearranged gives 'iols'.
'iols' going around 'd' is 'IDOLS'.
(Other definitions for idols that I've seen before include "Solid (anag.)" , "False gods" , "Much-admired persons" , "Heroes" , "Graven images sometimes worshipped" .)