blackflagged 

a strong suggestion to avoid a person at all costs.

Behind Susie's back Wilkie formed the two-fingered x sign above her head - blackflagging her in no uncertain terms to Jimmy who had approached unsuspectingly with the intention of spading her.

blackflagged by angela June 6, 2003

blackflagged 

To have poisoned insects or critters. Derived from a trademark named insecticide.

Yolanda blackflagged her crabs with lindane.

blackflagged by harry flashman July 10, 2003

black flagged

to do something fucked up or wrong. Usually followed by someone waving a small black flag and the words "You done fucked up, son"

Tynise black flagged when she texted the wrong person. Twice.

black flagged by DistructiveHamster September 15, 2013

Black flagged

Getting really wasted and fucking up all night long usually with a big group of friends.

Mark was chugging four locos when he got up and shoved Christian hard on the toilet.He was so black flagged.

Black flagged by Myersgirl November 2, 2013