Different criteria have been transmitted for a major sin: an explicit threat of Hell, a specified penalty or grave warning, a particularly severe scriptural condemnation, or persistence in disobedience. These criteria are not necessarily word-for-word equivalent definitions. Some state a feature of the offense, while others provide a marker used to recognize it.
A clear warning establishes the seriousness of a sin; the omission of an offense from another short list does not weaken its prohibition. Both the relevant texts and what they actually indicate must be considered.