Loving covering new decking (8)
I believe the answer is:
adorning
'decking' is the definition.
(adorn can mean to deck or decorate)
'loving covering new' is the wordplay.
'loving' becomes 'adoring' (adore means to love or be very fond of).
'covering' means one lot of letters goes inside another.
'new' becomes 'n' (common abbreviation eg NT for New Testament).
'adoring' enclosing 'n' is 'ADORNING'.
(Other definitions for adorning that I've seen before include "Decorating, embellishing" , "Decorating with ornaments" , "decking" .)