Protective garment some initially make fun of (5)
I believe the answer is:
smock
'protective garment' is the definition.
(smock is a kind of protective garment)
'some initially make fun of' is the wordplay.
'initially' says to take the initial letters.
'make fun of' becomes 'mock' (I've seen this before).
The initial letter of 'some' is 's'.
's'+'mock'='SMOCK'
(Other definitions for smock that I've seen before include "artist's attire" , "Artist's loose overall" , "Loose dress or blouse" , "Loose outer garment" , "Artist's, peasant's, overall" .)