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.
To a great extent; extremely.
In an incredible manner; not to be believed.
Used to note the surprising or hard-to-believe nature of what is being said and suggest that it is nevertheless true.