I can't seem to find any definite earliest example of this expression, or a reason why "hissy" was chosen to describe a tantrum. Does anyone hiss when they are angry? When and why was the phrase coined?
Learn English – the origin of “hissy fit”
etymologyidioms
Best Answer
The OED included hissy fit in their entry for hissy, writing:
The 1967 usage is the first recorded usage that they give, so the phrase is relatively new. They suggest that this use of hissy is tied to hysterics, and they add:
It seems possible that hissy came first--someone would go into hysterics and throw a tantrum if they didn't get their way. This eventually changed to become a hissy fit, or a "fit of hysterics". Note that there isn't a firm indication of origins, but this is the theory presented by the OED.