Nothing may be seen in nasty thin material (5)
I believe the answer is:
voile
'thin material' is the definition.
'voile' can be an answer for 'material' (I've seen this before). I am not sure about the 'thin' bit.
'nothing may be seen in nasty' is the wordplay.
'nothing' becomes 'O' (looks like zero - 0).
'may be seen in' is an insertion indicator.
'nasty' becomes 'vile' (synonyms).
'o' placed into 'vile' is 'VOILE'.
Can you help me to learn more?
(Other definitions for voile that I've seen before include "Light semi-transparent fabric" , "Sheer fabric" , "fine material" .)