FAULTLESSLY
faultlessly
(adverb) without a fault; in a faultless manner; “he solved all the problems faultlessly”
Source: WordNet® 3.1
Etymology
Adverb
faultlessly (comparative more faultlessly, superlative most faultlessly)
In a faultless manner
Source: Wiktionary
FAULTLESS
Fault"less, a.
Definition: Without fault; not defective or imperfect; free from blemish;
free from incorrectness, vice, or offense; perfect; as, a faultless
poem.
Whoever thinks a faultless piece to see, Thinks what ne'er was, nor
is, nor e'er shall be. Pope.
Syn.
– Blameless; spotless; perfect. See Blameless.
– Fault"less*ly, adv.-Fault"less*ness, n.
Source: Webster’s Unabridged Dictionary 1913 Edition