That 'fat chance' means 'a small chance' (and is always used sarcastically) is clear to me. But what I was wondering about is if the term used to be factual and then changed meaning because it started to be used in a sarcastic way, or has it always been sarcastic and was it never used literally?
(Is that latter option even possible? Isn't it so that the sarcasm actually only works if everybody knows that underneath 'fat' means 'big' here? But I'm above all curious if it ever was a normal term, such as 'slim chance' still is)
Best Answer
I found a few early instances where the use seems to refer to a significant chance, or even an exorbitant or undeserved opportunity, but this intended meaning appears to be rare and was rapidly overwhelmed by the figurative meaning.
Here are a few of the clippings I collected where "fat chance" seems to mean a big chance:
1860
1873
1895