spilt: (verb, past tense of to spill) to allow or cause contents of a container to overflow the edges (including people from a building); to reveal information that should have been kept confidential
split: (verb) to break or tear into parts; to divide into shares; to separate; (noun) a break or tear
“Spilt” and “split” are also both past participles which can be used as adjectives. Split pea soup, whether you are a fan of it or not, is better than spilt pea soup.
“Spilt” is the original British past tense of “to spill”, and “spilled” is the American version. Although “spilt” is still used in the United Kingdom, it is becoming less common, and “spilled” is gaining in popularity—as the past tense, not as a condition of soup.