In open spite, lament paint variety (7)
I believe the answer is:
acrylic
'paint variety' is the definition.
(I've seen this in another clue)
'in open spite lament' is the wordplay.
'in' indicates putting letters inside.
'open spite' becomes 'alic' (I can't justify this - if you can you should give a lot more credence to this answer).
'lament' becomes 'cry' (I've seen this in another clue).
'alic' placed around 'cry' is 'ACRYLIC'.
Can you help me to learn more?
(Other definitions for acrylic that I've seen before include "fibre that's synthetic" , "material for coat?" , "Pungent acid" , "The synthetic fibre is icy, Carl" , "Synthetic fabric" .)