A CLAP Trap, a name given to the rant and rhimes that dramatick poets, to please the actors, let them go off with; as much as to say, a trap to catch a clap by way of applause from the spectators at a play. [Bailey, "Dictionarium Britannicum," London, 1730]
"reduce to poverty," mid-15c., from beggar (n.). From c. 1600 as "exceed the means of," hence "to outdo." Related: Beggared; beggaring.
a slighting word for "a device, a contrivance," 1825, western England dialect, origin obscure, perhaps from con(trive) + trap, or deception.