A cuntador is a person who doesn't play fair, whether in sport, business or life. Someone who uses another person's misfortune to gain something for themselves.
Originated when the cyclist Alberto Contador, took an unfair advantage of cyclist Andy Schleck's bike malfunction on stage 16 of the 2010 Tour de France.
Similar to fucktard, this word is a portmanteau of cunt and retard. While fucktard is associated with activly acting like a fucking retard, a cuntard is more passive and just sits there acting like a retarded cunt.