RichThesaurus
lethargically
vs
sluggishly
lethargically
adv
In a lethargic manner, without energy, tiredly.
sluggishly
adv
In a sluggish manner; responding or moving slowly.
How often have the words
lethargically
and
sluggishly
occurred in a corpus of books?
(source:
Google Ngram Viewer
)