Deception defines ones capacity to fool someone in believing something other than truth, by means of disguise or lies.
Deception can get crafty ones very far in life, with caution. If one is aware they've been deceived, they may respond very strongly. This could be used to the deceivers benefit, however if unintentional, this is almost always a detriment instead. People may hold onto very long grudges, people may lose companionship in you, and if grave enough of a dupe, people may even come for your head.
Deception can not only be used for wearing a disguise to hide your identity, but even attempting Stealth. A useful Skill for one that is trying to play with words, and have others wrapped around your finger in various ways.