Most of these are generally quite similar. In terms of the differences: A 'slip' in this context is a minor, unimportant mistake. 'You made a slip in your answer for question 6. You should have added Y instead of subtracting it'. 'There was only one slip in his singing'. An error is usually only used for numbers, calculations, and words, rather than physical things. 'This formula has an error in the weight'. 'You made an error in adding up the charges'. A fault is when something goes wrong. Unlike the others, it usually isn't made by a human. 'My mixer has a fault. It won't change speed'. 'There is a fault in this cloth'. An inaccuracy is quite different. It is literal. This is a lack of accuracy, which is related to measurements. 'An inaccuracy in measuring the ingredients will make the cake fail to rise'. 'If you don't let the meter settle, your reading will be inaccurate'.