Superficial sort covered in ooze (4-4)
I believe the answer is:
skin-deep
'superficial' is the definition.
(I've seen this before)
'sort covered in ooze' is the wordplay.
'sort' becomes 'kind' (synonyms).
'covered in' means one lot of letters goes inside another.
'ooze' becomes 'seep' (synonyms).
'kind' inserted inside 'seep' is 'SKIN-DEEP'.
(Other definitions for skin-deep that I've seen before include "Superficial, beauty perhaps" , "Superficial like body graze" , "Superficial as beauty is said to be" , "Develop" , "The depth of beauty" .)