Answer: SISS

AnswerCrossword Clue
SISSSound from a pressure cooker.
sissa form of sister
SISSMake a sibilant sound
SISSLeaky noise
SISSSnake sound
SISSLeaking radiator's sound
SISSSound of escaping steam
SISSRadiator sound
SISSSound of a reptile or steam
SISSSibilant sound
SISSHissing sound
SISSSnaky sound
SISSBefore "boom, bah"
SISSSibilant sound of derision
SISSMake a hissing sound.
SISSDeflation sound
SISSSteamy sound.
SISSSizzle.
SISSSibilant interjection.
SISSHissing sound.
SISSFie!
SISSSound of a boiling kettle.
SISSSound of escaping steam.
SISSSibilant sound.
SISSNoise made by water dropped on a hot store.
SISSJap sound indicating politeness.
SISSHiss.
SISSPuncture sound
SISSGreeting for the villain
SISSk.d. lang and The ... Boom Bang