Thin Red Line 

1)The crevice of a girl's vagina seen from the outside of her underwear. Also known as camel-toe.

2) A WW2 movie from 1998 directed by Terrence Malick.

1) John: "I saw Sirah's thin red line as she got out of the pool, it was sexy."

2) John: "I watched the Thin Red Line on TNT yesterday."

Thin Red Line by neineinein329 July 8, 2015

Thin Red Line 

Thin Red Line is another negative adjective such as piece of crap, POS, HUD, etc. Its derivation is from the Terrence Malik travesty of the same name.

Wow, the Cubs sure suck. They're nothing but a Thin Red Line.

or

Eating at that restaurant made me vomit for hours. It was so Thin Red Line.

Thin Red Line by westudi September 28, 2006