In Skyfall, besides describing woman as a challenge, the word also describes the woman as a temptress, an alluring woman who seduces and/or exploits men. So bond pretty much covered everything in a woman, alluring, seductive, challenging, and with a possibility of exploiting her man.

A pubic hair piece. A toupee for the pubic area/genitals. In the 1700’s when mercury was used to treat sexually transmitted diseases (Gonorrhea or Syphilis) one of the side effects was the loss of pubic hair. To disguise this condition, that was not cured by mercury, a Merkin was employed.

The term you probably heard in Skyfall, in that particular context, Provocatrix means a Challenger, and a Challenger (female) in that context means something or someone challenging. So, Bond described a woman as a "challenge."