MONOTONOUSLY
monotonously
(adverb) in a monotonous manner; “the history of the play throughout the latter part of the eighteenth century is monotonously uneventful”
Source: WordNet® 3.1
Etymology
Adverb
monotonously (comparative more monotonously, superlative most monotonously)
In a manner that is tedious, repetitious or lacking in variety.
In a droning manner, that does not change pitch.
Source: Wiktionary
MONOTONOUS
Mo*not"o*nous, a. Etym: [Gr. Tone.]
Definition: Uttered in one unvarying tone; continued with dull uniformity;
characterized by monotony; without change or variety; wearisome.
– Mo*not"o*nous*ly, adv.
– Mo*not"o*nous*ness, n.
Source: Webster’s Unabridged Dictionary 1913 Edition