It's pretty open material (4)
I believe the answer is:
lace
'material' is the definition.
(I know that lace is a type of material)
'it's pretty open' is the wordplay.
I cannot really understand how this works, but
'it' could be 'e' ('e' can mean 'electronic' which is similar to 'IT') and 'e' is present in the answer.
The remaining letters 'lac' is a valid word which might be clued in a way I don't understand.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for lace that I've seen before include "Shoe string" , "Delicate fabric woven in an open web" , "Shoe cord" , "A fabric; add alcohol to" , "Fabric made in openwork design" .)