The word "slip" has multiple meanings and a variety of synonyms. For instance, to slip on ice is to skid, slide or lose your footing. To slip a note under someone's door is to sneak, quietly place or slide. To slip into a cozy robe is to put on, get dressed or change into. If someone makes a slip-up, it could also mean that they made a mistake, blunder or error. Finally, if you slip a disk in your back you could have herniated, ruptured or bulging disk. As we can see, there are a plethora of ways to express the same idea as slip in our language.