Know somebody in the biblical sense
Definition 1 of 1
Pro Tip 1/3Idiomatic Origin
The phrase originates from how the Bible refers to sexual relations, often using 'knew'. 
In the historical context, heroes often 'knew' their wives, meaning they were intimate.
Pro Tip 2/3Cultural Sensitivity
Some may find it offensive due its religious linkage. Use it with awareness of the audience. 
Be cautious when saying 'she knew him in the biblical sense', especially in conservative settings.
Pro Tip 3/3Euphemistic Nature
It's a euphemism, so it's less direct and can soften the impact of referring to sex. 
He joked that they hadn't been introduced in the biblical sense yet, eliciting a chuckle.