Add or take away new gaudy covering (7)
I believe the answer is:
garnish
'add or' is the definition.
I can't tell whether this defines the answer.
'away new gaudy covering' is the wordplay.
'away new' becomes 'n' (common abbreviation eg NT for New Testament. I am not sure about the 'away' bit.).
'gaudy' becomes 'garish' (synonyms).
'covering' means one lot of letters goes inside another.
'n' placed inside 'garish' is 'GARNISH'.
'take' acts as a link.
Can you help me to learn more?
(Other definitions for garnish that I've seen before include "Dress - trimmings" , "Decorate, embellish" , "It's added to a dish for flavour or decoration" , "Adornment" , "Decorate with herbs" .)