Wiktionary
plungingly
adv. With a motion like a plunge.
Usage examples of "plungingly".
From this frozen encounter with spirit it was terror that finally released me, and I ran blindly, plungingly, in any direction I could find in far greater fear than I had run from the hooligans in Arden.
Fred hesitated an instant and then went on plungingly, "I might go into the Church now.