Answer: flippant

AnswerCrossword Clue
FLIPPANTImpudent
FLIPPANTLacking seriousness
FLIPPANTPert
FLIPPANTSarcastic
FLIPPANTNot very serious
FLIPPANTCheeky
flippantfrivolously disrespectful or lacking in seriousness
flippantimpudent (insolently disrespectful)