The Collaborative International Dictionary
Remurmur
Remurmur \Re*mur"mur\ (r?-m?r"m?r), v. t. & i. [Pref. re- + murmur: cf. F. remurmurare.] To murmur again; to utter back, or reply, in murmurs.
The trembling trees, in every plain and wood,
Her fate remurmur to the silver flood.
--Pope.
Wiktionary
remurmur
vb. To murmur back or again; to reply in murmurs.