How does someone accidentally make an oath? Leviticus 5:4

How does someone accidentally make an oath (an oath that they are "unaware" they had made)? Does it mean basically all careless statements about taking a particular action are in effect an oath? > ... or if anyone thoughtlessly takes an oath to do anything, whether good or evil (in any matter one might carelessly swear about) even though they are unaware of it, but then they learn of it and realize their guilt— when anyone becomes aware that they are guilty in any of these matters, they must confess in what way they have sinned. I'm interested primarily in the exegesis—what this passage literally meant—not the modern application. An oath made while drunk is a possible example, but I'm not even sure that fits. If that was the only case, wouldn't it just say "an oath made while drunk"? What other cases might there be?