1) Indiscretion 2) Minor misdeed 3) Minor offense 4) Minor sin or fault 5) Minor sin or petty fault 6) Minor transgression 7) Minor wild oat 8) Misbehavior 9) Misbehaviour 10) Misdeed 11) Petty misdeed 12) Slight sin 13) Slip 14) Small sin 15) Small transgression 16) Trifling fault Found on https://www.crosswordclues.com/clue/peccadillo
Pec`ca·dil'lo noun ; plural Peccadillos . [ Spanish pecadillo , dim. of pecado a sin, from Latin peccatum . See Peccant .] A slight trespass or offense; a petty crime or fault. Sir W. Scott. Found on http://www.encyclo.co.uk/webster/P/38