Many lies are white ones (6)
I believe the answer is:
lilies
'white ones' is the definition.
Although both the answer and definition are plural nouns, I can't understand how one could define the other.
'many lies' is the wordplay.
'many' becomes 'li' (I am not sure about this - if you are sure you should believe this answer much more).
'li'+'lies'='LILIES'
'are' acts as a link.
Can you help me to learn more?
(Other definitions for lilies that I've seen before include "Flowering plants" , "'Showy flowers, most have a strong smell (6)'" , "'''Consider the ... of the field, how they grow'' (Bible) (6)'" , "Flowers for when 'e is ill" , "Plants with slender stems and large trumpet-shaped flowers" .)