Reportedly achieved end of war, not like Bikini (3-5)
I believe the answer is:
one-piece
'of war not like bikini' is the definition.
I can't tell whether this definition defines the answer.
'reportedly achieved end' is the wordplay.
'reportedly' shows a homophone (sound like).
'achieved' becomes 'won' (win can mean to earn or achieve).
'end' becomes 'piece' (I can't justify this - if you can you should believe this answer much more).
'won' is a homophone of 'one'.
'one'+'piece'='ONE-PIECE'
Can you help me to learn more?
(Other definitions for one-piece that I've seen before include "Made as a single item" , "Made as a single unit" , "Bathing-costume" , "(E.g. swimming costume) not as separates" .)