EFFICACIOUSLY
efficaciously, effectively
(adverb) in an effective manner; “these are real problems that can be dealt with most effectively by rational discussion”
Source: WordNet® 3.1
Etymology
Adverb
efficaciously (comparative more efficaciously, superlative most efficaciously)
in an efficacious manner
Source: Wiktionary
EFFICACIOUS
Ef`fi*ca"cious, a. Etym: [L. eficax, -acis, fr. efficere. See Effect,
n.]
Definition: Possessing the quality of being effective; productive of, or
powerful to produce, the effect intended; as, an efficacious law.
Syn.
– See Effectual.
– Ef`fi*ca"cious*ly, adv.
– Ef`fi*ca"cious*ness, n.
Source: Webster’s Unabridged Dictionary 1913 Edition