1. To mix some substance, typically alcohol or drugs of some kind, into another, especially without the knowledge of other people. Often used in passive constructions. You're going to lace the punch with booze? Do you know how childish and cliché that is? When she woke up the next morning, her friend told her that her drink had been laced with kind of blackout drug, and they had all carried her home in a taxi to make sure she was safe.

2. To adulterate something, such as the truth, with something unnecessary or corrupting. Often used in passive constructions. The state-sponsored news network always laces stories with pro-government propaganda. I know you have this idea in your head about what happened, but remember that our memories are laced with all kinds of mistakes and fabrications.