Answer: SNAPPIEST

AnswerCrossword Clue
SNAPPIESTMost irritable
SNAPPIESTMost like Dorothy Parker's comebacks
SNAPPIESTMost lively
SNAPPIESTMost impatient
SNAPPIESTSharpest.
SNAPPIESTMost like Dapper Dan
snappiestIrritable and inclined to speak sharply; snappish
snappiestSNAPPY, snappish (tending to behave in an impatient or irritable manner)
snappiestCleverly concise; neat
snappiestNeat and elegant