dupe 
(dp, dyp)
(dp, dyp)n.
A person who is easily deceived or is used to carry out the designs of another.
tr.v. duped, dup·ing, dupes
To deceive (an unwary person). See Synonyms at deceive.
[French, from Old French, probably alteration of huppe, hoopoe (from the bird's somewhat foolish appearance); see HOOPOE.]
dup′a·bili·ty n.
dupa·ble adj.
duper n.