a romantic connection that is vague, flirtatious, or not publicly defined as a committed relationship

他们俩现在的关系非常模糊，正处于一种暧昧关系中。

a secretive, shady, or adulterous relationship that is often morally questionable

这起丑闻揭露了这位官员与多名女性之间的暧昧关系。