unfaithfully
/"+/ (ame, mw)
unfaithfully — adverb
1. behaving in a way that breaks a promise of loyalty to someone who trusts you, es
behaving in a way that breaks a promise of loyalty to someone who trusts you, especially by having a secret romantic or sexual relationship with another person
Yumi found a receipt in her boyfriend's jacket and realized he had been behaving unfaithfully.
behaving unfaithfully — discovery of infidelity context
The detective's report confirmed the businessman was living unfaithfully with a colleague from Shanghai.
Ayesha moved to a different city after her husband acted unfaithfully with a neighbor.
Jude swore to his partner that he had never behaved unfaithfully during their months apart.
Ryan promised his wife he would stay loyal but was acting unfaithfully within a year.
- disloyally
broader — can apply to any relationship (friends, country, employer), not just romantic partners
- treacherously
stronger — implies a deliberate and harmful deception, often with serious consequences
- adulterously
narrower — only applies to married people having extramarital sex; formal or legal register
- faithfully
direct opposite — acting with loyalty and commitment toward a partner
- loyally
emphasizes steady support and devotion in any relationship
用法筆記
Typically pairs with verbs of behavior such as act, behave, or live. Almost always describes romantic or marital infidelity rather than other forms of disloyalty.