peccadillo(n = noun.act) indiscretion - a petty misdeed;
is a kind of misbehavior, misbehaviour, misdeed

   A slight trespass or offense; a petty crime; a trifling fault. Sir W. Scott. [1913 Webster]

peccadillo, n. (pl. -oes or -os) a trifling offence; a venial sin.

Etymology:
Sp. pecadillo, dimin. of pecado sin f. L (as PECCANT)

N  guilt, guiltiness, culpability, criminality, criminousness, deviation from rectitude, sinfulness, misconduct, misbehavior, misdoing, misdeed, malpractice, fault, sin, error, transgression, dereliction, delinquency, indiscretion, lapse, slip, trip, faux pas, peccadillo, flaw, blot, omission, failing, failure, break, bad break!, capital crime, delictum, offense, trespass, misdemeanor, misfeasance, misprision, malefaction, malfeasance, malversation, crime, felony, enormity, atrocity, outrage, deadly sin, mortal sin, deed without a name, corpus delicti, guilty, to blame, culpable, peccable, in fault, at fault, censurable, reprehensible, blameworthy, uncommendable, illaudable, weighed in the balance and found wanting, exceptionable, in flagrante delicto, red-handed, in the very act, with one's hand in the cookie jar, cui prodest scelus in fecit, culpam paena premit comes, O would the deed were good!, responsibility prevents crimes se judice nemo noce, so many laws argues so many sins.