English
infidelly
From infidel + -ly.
Formed from infidel + -ly
Proto-Indo-European *bʰeydʰ- ‘to command, to persuade, to trust’
Latin fidēs ‘faith, trust’
Latin fidēlis ‘faithful’
Latin īnfidēlis ‘unfaithful’
Middle French infidèle ‘unfaithful’
English infidel
Today it means
adv In an infidel manner.
Language periods are conventional ranges, not dates for this word.
Etymograph / infidelly