Most importantly.
In front, prominently forward.
First in time.
Positioned in front of (all) others in space, most forward.
Coming before (all) others in time.
Closest to the bow.
Of the highest rank or position; of the greatest importance; of the highest priority.
Very.
Mightily.
Mighty; competent; capable; strong; powerful.
Substantial; weighty; of import.
Able; able to occur; possible.