Source : Webster's Revised Unabridged Dictionary (1913)

Peccadillo \Pec`ca*dil"lo\, n.; pl. {Peccadillos}. [Sp.
   pecadillo, dim. of pecado a sin, fr. L. peccatum. See
   {Peccant}.]
   A slight trespass or offense; a petty crime or fault. --Sir
   W. Scott.