In favour of wearing article, protective garment (5)
I believe the answer is:
apron
'protective garment' is the definition.
(apron is a kind of protective garment)
'in favour of wearing article' is the wordplay.
'in favour of' becomes 'pro' (I've seen this before).
'wearing' means one lot of letters goes inside another.
'article' becomes 'an' (indefinite article).
'pro' going into 'an' is 'APRON'.
(Other definitions for apron that I've seen before include "standing" , "Area for aircraft not in use" , "Protective garment worn at front" , "Kitchen protector" , "stage perhaps" .)