To root for someone is to cheer them on or offer moral support to them, so Jack was telling WIll that he was still cheering him on and hoping he would win the fight.

OMG!!! i loved this movie so much….the action was great and johnny depp is the hottest thing alive! after jack encountered davey jones at sea and everyone decided to go out there and get him i was totally waiting for another half an hour to go on. they should have stopped before they show him being eating. that would have been a great start. this movie was greta but it’s not the kindof movie that you can watch by itself on video. it was like a free tasting and now we have to buy the candy bar that doesn’t come out until next year (pirates 3.) so, great movie/BAD ending. but it was smart of them, you must admit, because now everyone has to see the next one too. but i agree with you.

Meriam Webster dates it to 1889:

Main Entry: 4root

Function: intransitive verb

Etymology: perhaps alteration of 2rout

Date: 1889

1 : to noisily applaud or encourage a contestant or team : cheer

2 : to wish the success of or lend support to someone or something

— root·er noun

It means “I’m still pulling for you. I’m still on your side, this is just business”. Rooting litereally means cheering. It was used in the 1920’s for cheering for your favorite team.

It means ‘barracking’ – like you do for your favourite sports team. It’s an American expression and sounds amusing to Australians. Rooting has quite a different meaning for us!

rooting means like……ok heres a sentence

“the football spectater was rooting for the knights team”

it means like going for or whatever

ARRGH, give Mike 10 pts , matey, and 2 rations of rum