it means Long Distance Flirt. it's like Long Distance Relationship but it's just flirting. No labels
It's so hard to be in an LDF.
Long Distance Friend. Not a relationship, just friends who live far apart, sometimes have never met in person and may have met over social media. Usually helps to have these, they stay out of drama.
Abby: Who even is Alice, Jenna? You talk about her all the time but I’ve never even met her!
Jenna: She’s my LDF!!
Abby: What the hell is an LDF?!
Jenna: Duh, Abby, it’s a long distance friend.