all-out (English) comes from English all, from Middle English all, from Old English eall, from Proto-West Germanic all, from Proto-Germanic allaz, from Proto-Indo-European h₂él- — to grow, nourish.
all-out (English): using every available means; covering all aspects...
Definitions
using every available means; covering all aspects...
Ancestry of “all-out”, step by step
all-out traces back through two separate lines of ancestry.