All-out Edit Meaning

1.

Giving as much effort as possible; not holding back.

'All' refers to everything, and 'out' is an intensifier. So 'all-out' means 'everything and more'.

1) Karen went all-out in the race, and won a gold medal.

2) Captain Barne's final act was to order an all-out assault on the fortress.

2.

to go balls deep, or to give it your all. to try really hard and give a situation 100% of your attention

"man, pedro really goes all-out"

See balls deep, go for it, deep

3.

not hold anything back, sparing nothing

Both sides went all-out when the game started.