INFECTIOUSLY
contagiously, infectiously
(adverb) in a contagious manner; “she was contagiously bubbly”
Source: WordNet® 3.1
Etymology
Adverb
infectiously (comparative more infectiously, superlative most infectiously)
In an infectious manner.
Source: Wiktionary
In*fec"tious*ly, adv.
Definition: In an infectious manner. Shak.
INFECTIOUS
In*fec"tious, a. Etym: [Cf. F. infectieux.]
1. Having qualities that may infect; communicable or caused by
infection; pestilential; epidemic; as, an infectious fever;
infectious clothing; infectious air; infectious vices.
Where the infectious pestilence. Shak.
2. Corrupting, or tending to corrupt or contaminate; vitiating;
demoralizing.
It [the court] is necessary for the polishing of manners . . . but it
is infectious even to the best morals to live always in it. Dryden.
3. (Law)
Definition: Contaminating with illegality; exposing to seizure and
forfeiture.
Contraband articles are said to be of an infectious nature. Kent.
4. Capable of being easily diffused or spread; sympathetic; readily
communicated; as, infectious mirth.
The laughter was so genuine as to be infectious. W. Black.
Syn.
– See Contagious.
Source: Webster’s Unabridged Dictionary 1913 Edition