<span>Who was the leader in Japan who advocated war with the United States during the 1940s? </span>Hideki Tojo
1 . The meaning of boo is to suddenly surprise someone.
Or , to show dissatisfaction and disapproval.
Also, a slang you could call your lover.
2. A boo could mean boyfriend or girlfriend .
3. Anyone calls anyone boo I guess .
They are right
Hope this helps good luck