Popularised by a television game show of the same name, where the loser of each round is dismissed by the host with the phrase "You are the weakest link, goodbye!". Used for people who are the weakest/least intelligent/slowest of a group.

When you eat dirt for the first time and leave your family to build a shack in the woods

Weakest Link, is a synonym for loser

1: The Weakest Link is a game show in which contestants answer a wide range of questions while trying to earn more money with each correct answer. The show first started in the UK in 2000, but has been done in many other countries as well.

This show was most popular for its UK host "Anne Robinson", who probably had to be the most annoying bitch on television at the time. Her shrill voice and expressionless face just left you wanting to reach out and throttle her.

2: Used to describe someone whos intelligence or physical abilities are less then average.

The greatest game show ever, primarily because of the former host who used to say "You are The Weakest Link! Goodbye!" in TEH GR347357 W4Y 3V3R!!! Unfortunately, she left the show, and NOBODY has the balls to truly take her place and make the show cool again.