immediately

adverb

1)

it was necessary to make a decision immediately

Syn:

straightaway, at once, right away, instantly, now, directly, promptly, forthwith, this/that (very) minute, this/that instant, there and then, then and there, on the spot, here and now, without delay, without further ado, posthaste; quickly, as fast as possible, speedily, as soon as possible; informal ASAP, pronto, double-quick, on the double, PDQ, in/like a flash, like a shot, tout de suite; humorous toot sweet; archaic forthright

2)

I sat immediately behind him

Syn:

directly, right, exactly, precisely, squarely, just, dead; informal smack dab