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